- Email: [email protected]
Effects of anesthesia on the electrolyte concentrations in blood and coelomic fluid of the earthworm, Pheretima Communissima
Camp. Biochem. P/~~siol. Vol. 79C, No. 2. pp. 277-219, Printed in Great Britain
EFFECTS
0306.4492/84 $3.00 + 0.00 ,i; 1984 PergamonPressLtd
OF ANESTHESIA
CONCENTRATIONS
CHITARU
OCURO,
of Biology,
ON THE ELECTROLYTE
IN BLOOD
OF THE EARTHWORM,
Department
1984
PHERETIMA
YUICHI SASAYAMA
Faculty
AND
COELOMIC
FLUID
COA4kfUNZSSZA4A
and KEISUKE NONAKA*
of Science, Toyama
University,
Toyama
930, Japan
(Received 16 March 1984) Abstract-l. Sodium, potassium, calcium and magnesium concentrations in blood and coelomic fluid of Pherefima communissimu under various methods of anesthesia or in the unanesthetized condition were
determined. 2. All electrolyte concentrations determined in ethanol-anesthetized earthworms were not significantly different from those in unanesthetized earthworms. 3. Thermal (warming, cooling) anesthesia, urethane and chloretone brought about increases or decreases in some electrolyte concentrations in the blood or coelomic fluid. However, not all electrolytes responded similarly to a method of anesthesia.
in the present study. Each group comprised 5-15 earthworms. In some earthworms, not all electrolyte concentrations were determined because of the small amount of blood or coelomic fluid obtained. The numbers of determinations are shown in Table 1. The earthworms were pinned on a dissecting board and the antero-dorsal body wall was cut open to expose the heart area. Blood was drawn directly into sharply pointed glass capillary tubes inserted into the dorsal vessel. Coelomic fluid was aspirated into glass capillary tubes from the body cavity. These manipulations were done with either anesthetized or unanesthetized animals under a binocular dissecting microscope. The blood and coelomic fluid obtained was centrifuged for 5 min at 12,000 rpm to eliminate the formed elements. After appropriate dilution of the samples, sodium (Na), potassium (K), calcium (Ca) and magnesium (Mg) concentrations were determined by atomic absorption spectrophotometry. Student’s t-test was employed for statistical analyses.
INTRODUCTION
Electrolyte concentrations in blood, coelomic fluid and urine have been determined in some species of annelids (Bahl, 1945, 1947; Roots, 1955; Kamemoto et al., 1962; Oglesby, 1970, 1973; Mangum and Johansen, 1975; Oglesby et al., 1982). The values reported vary among different species and with different environmental conditions. While studying electrolyte concentrations in the blood of earthworms for comparison with other annelid species, the writers discovered that concentrations of some electrolytes in blood and coelomic fluid were markedly different when different methods of anesthesia was used. The following are brief notes on the effects of anesthesia on the electrolyte concentrations in blood and coelomic fluid of the earthworm, Pheretima communissima. MATERIALS
AND
METHODS RESULTS
Earthworms, Pheretima communissima (Goto and Hatai), were collected from a fixed area of the University campus. They were anesthetized by one of the following methods immediately after collection.
Although it is difficult to ascertain which values are closest to those of the intact or undisturbed earthworms, the values from the unap.esthetized earthworms were adopted as a standard. Concentrations of all electrolytes in the blood of ethanol-anesthetized earthworms were not statistically different from those in blood of the unanesthetized earthworms. Every treatment tended more or less to decrease the blood Na concentrations. Among these, warming (- 15x), cooling (- 15%) and chloretone (- 12%) caused statistically significalLL decreases from the values of the unanesthetized earthworms. Urethane caused a 6:/, decrease but the value was not statistically significantly different from that of the controls. Warming and urethane tended to increase (+ 13%) and to decrease (- 14%) the blood K concentrations, respectively. However, these values were not statistically significantly different from those in the controls. The blood K concentration was increased markedly by cooling ( + 77%) and decreased markedly by chloretone (-40x), both deviations being significantly different from the values in the controls.
(1) Warming: earthworms were placed in a plastic bag and then the bag was immersed in a water bath at 4o“C. Under these conditions, the earthworms became immobile within 10 min. (2) Cooling: earthworms were placed in a plastic bag and then the bag was put in a freezer kept at -15°C. Ten minutes later the earthworms became immobile. (3) Ethanol: earthworms were immersed in 15% ethanol for 10min at room temperature (20°C). (4) Ethyl carbamate (urethane): earthworms were immersed in a 5% urethane aqueous solution for 10min at room temperature. (5) Acetonechloroform (chloretone): earthworms were immersed in a 0. l”/0 chloretone aqueous solution for 10 min at room temperature. Treatments (3). (4) and (5) anesthetized earthworms completely. Unanesthetized earthworms were used for controls *Present address: Research Laboratory, Sanwakagaku Kenkyusho Co. Ltd., Kasugai, Aichi 486, Japan. 277
278
CHITARU Table
1. Electrolyte
concentrations
in blood
and coelomic
OGURO et al. fluid of Pherelima
communissima.
Values are mean + SEM (N)
ITIM/ Treatment Blood Unanesthetized Ethanol (15%) Warming Cooling Urethane (5%) Chloretone (0.1%) Coelomic fluid &anesthetized Ethanol (15%) warming Cooling Urethane (So’) Chloretone $.l%) Asterisks
show statistical
Na
-__~ 87.68 85.98 74.69 74.57 81.67 77.32
f 5 + i + f
93.94 96.69 87.67 60.01 84.72 78.66
* 3.21 (6) * 3.59 (4) & 2.47 (14) + 4.24 (9)*** -). 1.53 (5)’ + 3.92 (6)*
significance
K
~_____. 3.25 (9) 1.64 (10) 4.58 (S)* 4.20 (7)* 1.42(5) 2.94 (6)*
compared
8.48 * 0.32 (9) 7.67t0.52(10) 9.45 kO.91 (12) 15.02 r 2.18 (7)** 7.27 f 0.48 (5) 5.11 k 0.31 (6)*** 9.68 t 0.70 (6) 9.48 jI 0.58 (4) 13.29t 1.08(14) 14.06 I: 1 .S I (9)* 8.11 iO.IP(S) 6.17 i 0.Y3 (6)*
with unanesthetized
The blood Ca in the earthworms with thermal anesthesia, warming or cooling, was significantly increased by 40% and 26’/$ respectively. The other agents did not have significant effects on blood Ca concentration. Thermal anesthesia did not affect blood Mg concentrations, however. A - IS% change in blood Mg concentration was observed upon cooling but the difference from the value in the control earthworms was not statistically significant. On the other hand, urethane (- 56%) and chloretone (550/,) anesthetized resulted in significant decreases in blood Mg concentration. The results are shown in Table 1 and Fig. 1. Changes in electrolyte concentrations in the coelomic fluid were in general similar to those observed in the blood electrolyte concentrations, as shown in Table 1. However, the Mg concentration tended to decrease in the coelomic fluid contrary to its tendency to increase in the blood.
% 60
Fig. 1. Effects of various methods of anesthesia on the electrolyte concentrations of Pheretima communissima. Values are the percentage from the unanesthetized earthworms. Ci Ethanol; B warming; q cooling; q urethane; lt&ichloretone.
Ca
specimens.
9.97 * 0.57 (9) 11.60i:0.74(10) 13.86 i_ 0.84(12)** 12.55 * 0.94 (7)* 8.93 i 0.50 (5) 10.33 * 0.41 (6) 4.49 rt 0.29 (6) 4.83 + 0.39 (5) 5.18~0.24(14) 5.35 &0.30(11) 4.05 * 0.02 (5) 4.20 rt 0.27 (6)
Mg 4.54 & 0.64 (9) 4.48 rf-0.33 (10) 4.82 + 0.63 (IO) 5.33 + 0.52 (7) 2.00 + 0.12 (5)’ X04&0.15(6)** 2.06 f 0.19 (6) 2.12 + 0.22 (5) 2.29 k 0.23 (14) 1.80~0.32(11) 1.31 fO.O1 (5)** 1.27 ? 0.1 I (6)**
*P < 0.05. **P < 0.01. ***p < 0.001.
Body wt also changed during 10 min of anesthesia. The largest effect was observed with ethanol (-9.0%). A minor change was observed with warming (-4.7%), cooling (-4.3%) or urethane (- 3.7%). Chloretone anesthesia tended to increase body wt (+ 2.4”/,).
DISCUSSION
The concentration of Na in the blood of the present species (87.7 mM/l) in an unanesthetized condition resembles that of Lumbricus terrestris and ~ellodr~llus caligi~osus under ethanol anesthesia (Kamemoto er al., 1962). However, the Na concentration (41.3 mM/l) in the blood of Pheretima posthum reported by Bahl (1947) was markedly lower, being half that of L. terrestris, H. caliginosus and the present species. The blood Na concentration of P. post~~m should be checked in the future since it is unlikely that the difference simply reflects species differetices. The reverse situation is seen for blood K concentration. While the value (8.5 mM/l) determined in the present species is close to that (7.9 mM/l) of H. caliginosus and slightly higher than that (5.5 mM/l) of L. terrestris, the value (18.9 mM/l) for P. poster seems to be extraordinarily high. Although a very high blood K concentration has been known to occur in some marine invertebrates (cf. Prosser and Brown, 1961), the value reported for P. posthum is beyond the average blood K concentrations in terrestrial forms. It was reported that in P. posthum that the concentration of Na in the blood is significantly lower than that in the coelomic fluid (Bahl, 1947). On the contrary, in L. terrestris and H. caliginosus the reverse situation was reported (Kamemoto et al., 1962). In the present species in an unanesthetized condition or under ethanol anesthesia the Na concentration is lower in the blood than in the coelomic fluid. Thus, the relationship between the Na concentrations of the blood and coelomic fluid in the present species is similar to that in P. posthum, although the difference is not so great. The relationship between the K concentrations in the blood and coelomic fluid was in general similar to that of Na. It was found in the present study that different methods of anesthesia resulted in difl’erent electrolyte
Earthworm
blood
in the blood and coelomic fluid of earthworms. The problem was how to identify a concentration. An un“normal” electrolyte anesthetized earthworm must suffer from the stress of trauma, which may affect blood electrolyte concentrations and/or water balance. However, in the present study the values from the unanesthetized earthworms were adopted as a standard (control). In P. communissima, the blood electrolyte concentrations of the individuals anesthetized with ethanol were not significantly different from those of the unanesthetized individuals. Thus, ethanol may be suitable for general use as an anesthetic in the earthworm. Incidentally, electrolyte concentrations reported previously for the blood and coelomic fluid of three species of earthworms were determined using ethanol anesthesia, which was believed to cause no effect on blood electrolyte concentrations (Bahi, 1947; Kamemoto, 1964). No reasons for that belief were presented. However, it was reported that in L. terrestris, the blood glucose level is not affected by ethanol anesthesia or by trauma (Lawrence et al., 1972). Urethane and chloretone in general brought about decreases in all electrolytes but Ca of the present species. On the other hand, thermal anesthesia caused a tendency for the blood K, Ca and Mg concentrations to increase, while blood Na tended to decrease. A similar relationship was observed in the K concentration in the coelomic fluid. Thus, not all electrolytes responded similarly to each method of anesthesia. It is known that the neuroendocrine system is involved in water and electrolyte regulation in earthworms (Kamemoto, 1964; Carley, 1975; Takeuchi, 1980a,b). However, analyses of the relationship between anesthesia and the neurosecretory system were not attempted in the present study but were instead left for future studies. Increases or decreases in blood electrolyte concentrations caused by anesthesia were not due simply to a change in electrolytes or water distribution between blood and coelomic fluid, since concentrations of an electrolyte in the blood and coelomic fluid did not always change in opposite directions. it is also noteworthy that each electrolyte had its own magnitude and direction of change. Furthermore, changes were not caused by hydration of dehydration of the earthworm as judged by the change in body wt. The concentrations
279
eiectroiyles
changes observed must be physiological or/and pharmacological responses to the anesthesia employed. REFERENCES Bahl K. N. (1945) Studies on the structure, development, and physiology of the nephridia of Oligochaeta. VI. The physiology of excretion and the significance of the enteronephric types of nephridial system in Indian earthworm. Q. Jl mirrosc. Sci. 85, 343-376. Bahl K. N. (1947) Excretion in the Oligochaeta. Biol. Rev. 22, 109-147. Carley W. W. (1975) Effects of brain removal on integumental water ~~eability and ion content of the earthworm Lumbricus terresfris. Gen. Camp. Endocrinoi. 27, 509-516. Kamemoto F. I. (1964) The influence of the brain on osmotic and ionic regulation in earthworms. Gen. Camp. Endocrinol. 4, 420-426. Kamemoto F. I., Spalding A. E. and Keister S. M. (1962) Ionic balance in blood and coelomic fluid of earthworms. Bial. Euft. 122, 228-23 1. Lawrence J. M., Graig J. V. and Clough D. (1972) The presence of a hyperglycemic factor in the suprapharyngeal ganglia of Lumbricus terrestris. Cen. Corn>. &ddcr&ol. 18, 260-267. Mangum C. P. and Johansen K. (I 975) The colloid osmotic pressure of invertebrate body fluid. J. e-up. &of. 63, 661-671. Oglesby L. C. (1970) Studies on the salt and water balance of Nereis diversicolor. I. Steady state temperature. Camp. Biochem. Physiol. 36, 449-466. Oglesby L. C. (1973) Salt and water balance in lugworms (Polychaeta: Arenicolidae), with special reference to Areniculu pact&a in Coos Bay, Oregon. Eiol. Bull. 145, 180-199. Oglesby L. C., Mangum C. P., Heacox L. E. and Ready N. E. (1982) Salt and water balance in the polychaete [email protected] sirens. Camp. Biochem. Physioi. 73A, 15-l 9. Prosser C. L. and Brown F. A. Jr. (1961) Comparutice Animal Physiology. Saunders, Philadelphia. Roots B. I. ( 1955) The water relations of earthworms. I. The activity of the nephrostome cilia of Lumhricus ferrestris L. and ~~~o~obophorueh~orot~ca Savigny, in relation to the concentration of the bathing medium. J. eq. Viol. 32, 765-774. Takeuchi N. (1980a) Effect of brain removal on the osmotic and ionic concentrations of the coelomic fluid of earthworms placed in soil and salt solutions. Camp. Biochem. Physiol. 67A, 347-352. Takeuchi N. (1980b) A possibility of elevation of the free amino acid level for the extra-cellular hy~rosmotic adaptation of the earthworm Eisenia &)etida (Sav.) to the concentrated external medium. Comp. Biochem. Physiol. 67A, 353-355.
EFFECTS
0306.4492/84 $3.00 + 0.00 ,i; 1984 PergamonPressLtd
OF ANESTHESIA
CONCENTRATIONS
CHITARU
OCURO,
of Biology,
ON THE ELECTROLYTE
IN BLOOD
OF THE EARTHWORM,
Department
1984
PHERETIMA
YUICHI SASAYAMA
Faculty
AND
COELOMIC
FLUID
COA4kfUNZSSZA4A
and KEISUKE NONAKA*
of Science, Toyama
University,
Toyama
930, Japan
(Received 16 March 1984) Abstract-l. Sodium, potassium, calcium and magnesium concentrations in blood and coelomic fluid of Pherefima communissimu under various methods of anesthesia or in the unanesthetized condition were
determined. 2. All electrolyte concentrations determined in ethanol-anesthetized earthworms were not significantly different from those in unanesthetized earthworms. 3. Thermal (warming, cooling) anesthesia, urethane and chloretone brought about increases or decreases in some electrolyte concentrations in the blood or coelomic fluid. However, not all electrolytes responded similarly to a method of anesthesia.
in the present study. Each group comprised 5-15 earthworms. In some earthworms, not all electrolyte concentrations were determined because of the small amount of blood or coelomic fluid obtained. The numbers of determinations are shown in Table 1. The earthworms were pinned on a dissecting board and the antero-dorsal body wall was cut open to expose the heart area. Blood was drawn directly into sharply pointed glass capillary tubes inserted into the dorsal vessel. Coelomic fluid was aspirated into glass capillary tubes from the body cavity. These manipulations were done with either anesthetized or unanesthetized animals under a binocular dissecting microscope. The blood and coelomic fluid obtained was centrifuged for 5 min at 12,000 rpm to eliminate the formed elements. After appropriate dilution of the samples, sodium (Na), potassium (K), calcium (Ca) and magnesium (Mg) concentrations were determined by atomic absorption spectrophotometry. Student’s t-test was employed for statistical analyses.
INTRODUCTION
Electrolyte concentrations in blood, coelomic fluid and urine have been determined in some species of annelids (Bahl, 1945, 1947; Roots, 1955; Kamemoto et al., 1962; Oglesby, 1970, 1973; Mangum and Johansen, 1975; Oglesby et al., 1982). The values reported vary among different species and with different environmental conditions. While studying electrolyte concentrations in the blood of earthworms for comparison with other annelid species, the writers discovered that concentrations of some electrolytes in blood and coelomic fluid were markedly different when different methods of anesthesia was used. The following are brief notes on the effects of anesthesia on the electrolyte concentrations in blood and coelomic fluid of the earthworm, Pheretima communissima. MATERIALS
AND
METHODS RESULTS
Earthworms, Pheretima communissima (Goto and Hatai), were collected from a fixed area of the University campus. They were anesthetized by one of the following methods immediately after collection.
Although it is difficult to ascertain which values are closest to those of the intact or undisturbed earthworms, the values from the unap.esthetized earthworms were adopted as a standard. Concentrations of all electrolytes in the blood of ethanol-anesthetized earthworms were not statistically different from those in blood of the unanesthetized earthworms. Every treatment tended more or less to decrease the blood Na concentrations. Among these, warming (- 15x), cooling (- 15%) and chloretone (- 12%) caused statistically significalLL decreases from the values of the unanesthetized earthworms. Urethane caused a 6:/, decrease but the value was not statistically significantly different from that of the controls. Warming and urethane tended to increase (+ 13%) and to decrease (- 14%) the blood K concentrations, respectively. However, these values were not statistically significantly different from those in the controls. The blood K concentration was increased markedly by cooling ( + 77%) and decreased markedly by chloretone (-40x), both deviations being significantly different from the values in the controls.
(1) Warming: earthworms were placed in a plastic bag and then the bag was immersed in a water bath at 4o“C. Under these conditions, the earthworms became immobile within 10 min. (2) Cooling: earthworms were placed in a plastic bag and then the bag was put in a freezer kept at -15°C. Ten minutes later the earthworms became immobile. (3) Ethanol: earthworms were immersed in 15% ethanol for 10min at room temperature (20°C). (4) Ethyl carbamate (urethane): earthworms were immersed in a 5% urethane aqueous solution for 10min at room temperature. (5) Acetonechloroform (chloretone): earthworms were immersed in a 0. l”/0 chloretone aqueous solution for 10 min at room temperature. Treatments (3). (4) and (5) anesthetized earthworms completely. Unanesthetized earthworms were used for controls *Present address: Research Laboratory, Sanwakagaku Kenkyusho Co. Ltd., Kasugai, Aichi 486, Japan. 277
278
CHITARU Table
1. Electrolyte
concentrations
in blood
and coelomic
OGURO et al. fluid of Pherelima
communissima.
Values are mean + SEM (N)
ITIM/ Treatment Blood Unanesthetized Ethanol (15%) Warming Cooling Urethane (5%) Chloretone (0.1%) Coelomic fluid &anesthetized Ethanol (15%) warming Cooling Urethane (So’) Chloretone $.l%) Asterisks
show statistical
Na
-__~ 87.68 85.98 74.69 74.57 81.67 77.32
f 5 + i + f
93.94 96.69 87.67 60.01 84.72 78.66
* 3.21 (6) * 3.59 (4) & 2.47 (14) + 4.24 (9)*** -). 1.53 (5)’ + 3.92 (6)*
significance
K
~_____. 3.25 (9) 1.64 (10) 4.58 (S)* 4.20 (7)* 1.42(5) 2.94 (6)*
compared
8.48 * 0.32 (9) 7.67t0.52(10) 9.45 kO.91 (12) 15.02 r 2.18 (7)** 7.27 f 0.48 (5) 5.11 k 0.31 (6)*** 9.68 t 0.70 (6) 9.48 jI 0.58 (4) 13.29t 1.08(14) 14.06 I: 1 .S I (9)* 8.11 iO.IP(S) 6.17 i 0.Y3 (6)*
with unanesthetized
The blood Ca in the earthworms with thermal anesthesia, warming or cooling, was significantly increased by 40% and 26’/$ respectively. The other agents did not have significant effects on blood Ca concentration. Thermal anesthesia did not affect blood Mg concentrations, however. A - IS% change in blood Mg concentration was observed upon cooling but the difference from the value in the control earthworms was not statistically significant. On the other hand, urethane (- 56%) and chloretone (550/,) anesthetized resulted in significant decreases in blood Mg concentration. The results are shown in Table 1 and Fig. 1. Changes in electrolyte concentrations in the coelomic fluid were in general similar to those observed in the blood electrolyte concentrations, as shown in Table 1. However, the Mg concentration tended to decrease in the coelomic fluid contrary to its tendency to increase in the blood.
% 60
Fig. 1. Effects of various methods of anesthesia on the electrolyte concentrations of Pheretima communissima. Values are the percentage from the unanesthetized earthworms. Ci Ethanol; B warming; q cooling; q urethane; lt&ichloretone.
Ca
specimens.
9.97 * 0.57 (9) 11.60i:0.74(10) 13.86 i_ 0.84(12)** 12.55 * 0.94 (7)* 8.93 i 0.50 (5) 10.33 * 0.41 (6) 4.49 rt 0.29 (6) 4.83 + 0.39 (5) 5.18~0.24(14) 5.35 &0.30(11) 4.05 * 0.02 (5) 4.20 rt 0.27 (6)
Mg 4.54 & 0.64 (9) 4.48 rf-0.33 (10) 4.82 + 0.63 (IO) 5.33 + 0.52 (7) 2.00 + 0.12 (5)’ X04&0.15(6)** 2.06 f 0.19 (6) 2.12 + 0.22 (5) 2.29 k 0.23 (14) 1.80~0.32(11) 1.31 fO.O1 (5)** 1.27 ? 0.1 I (6)**
*P < 0.05. **P < 0.01. ***p < 0.001.
Body wt also changed during 10 min of anesthesia. The largest effect was observed with ethanol (-9.0%). A minor change was observed with warming (-4.7%), cooling (-4.3%) or urethane (- 3.7%). Chloretone anesthesia tended to increase body wt (+ 2.4”/,).
DISCUSSION
The concentration of Na in the blood of the present species (87.7 mM/l) in an unanesthetized condition resembles that of Lumbricus terrestris and ~ellodr~llus caligi~osus under ethanol anesthesia (Kamemoto er al., 1962). However, the Na concentration (41.3 mM/l) in the blood of Pheretima posthum reported by Bahl (1947) was markedly lower, being half that of L. terrestris, H. caliginosus and the present species. The blood Na concentration of P. post~~m should be checked in the future since it is unlikely that the difference simply reflects species differetices. The reverse situation is seen for blood K concentration. While the value (8.5 mM/l) determined in the present species is close to that (7.9 mM/l) of H. caliginosus and slightly higher than that (5.5 mM/l) of L. terrestris, the value (18.9 mM/l) for P. poster seems to be extraordinarily high. Although a very high blood K concentration has been known to occur in some marine invertebrates (cf. Prosser and Brown, 1961), the value reported for P. posthum is beyond the average blood K concentrations in terrestrial forms. It was reported that in P. posthum that the concentration of Na in the blood is significantly lower than that in the coelomic fluid (Bahl, 1947). On the contrary, in L. terrestris and H. caliginosus the reverse situation was reported (Kamemoto et al., 1962). In the present species in an unanesthetized condition or under ethanol anesthesia the Na concentration is lower in the blood than in the coelomic fluid. Thus, the relationship between the Na concentrations of the blood and coelomic fluid in the present species is similar to that in P. posthum, although the difference is not so great. The relationship between the K concentrations in the blood and coelomic fluid was in general similar to that of Na. It was found in the present study that different methods of anesthesia resulted in difl’erent electrolyte
Earthworm
blood
in the blood and coelomic fluid of earthworms. The problem was how to identify a concentration. An un“normal” electrolyte anesthetized earthworm must suffer from the stress of trauma, which may affect blood electrolyte concentrations and/or water balance. However, in the present study the values from the unanesthetized earthworms were adopted as a standard (control). In P. communissima, the blood electrolyte concentrations of the individuals anesthetized with ethanol were not significantly different from those of the unanesthetized individuals. Thus, ethanol may be suitable for general use as an anesthetic in the earthworm. Incidentally, electrolyte concentrations reported previously for the blood and coelomic fluid of three species of earthworms were determined using ethanol anesthesia, which was believed to cause no effect on blood electrolyte concentrations (Bahi, 1947; Kamemoto, 1964). No reasons for that belief were presented. However, it was reported that in L. terrestris, the blood glucose level is not affected by ethanol anesthesia or by trauma (Lawrence et al., 1972). Urethane and chloretone in general brought about decreases in all electrolytes but Ca of the present species. On the other hand, thermal anesthesia caused a tendency for the blood K, Ca and Mg concentrations to increase, while blood Na tended to decrease. A similar relationship was observed in the K concentration in the coelomic fluid. Thus, not all electrolytes responded similarly to each method of anesthesia. It is known that the neuroendocrine system is involved in water and electrolyte regulation in earthworms (Kamemoto, 1964; Carley, 1975; Takeuchi, 1980a,b). However, analyses of the relationship between anesthesia and the neurosecretory system were not attempted in the present study but were instead left for future studies. Increases or decreases in blood electrolyte concentrations caused by anesthesia were not due simply to a change in electrolytes or water distribution between blood and coelomic fluid, since concentrations of an electrolyte in the blood and coelomic fluid did not always change in opposite directions. it is also noteworthy that each electrolyte had its own magnitude and direction of change. Furthermore, changes were not caused by hydration of dehydration of the earthworm as judged by the change in body wt. The concentrations
279
eiectroiyles
changes observed must be physiological or/and pharmacological responses to the anesthesia employed. REFERENCES Bahl K. N. (1945) Studies on the structure, development, and physiology of the nephridia of Oligochaeta. VI. The physiology of excretion and the significance of the enteronephric types of nephridial system in Indian earthworm. Q. Jl mirrosc. Sci. 85, 343-376. Bahl K. N. (1947) Excretion in the Oligochaeta. Biol. Rev. 22, 109-147. Carley W. W. (1975) Effects of brain removal on integumental water ~~eability and ion content of the earthworm Lumbricus terresfris. Gen. Camp. Endocrinoi. 27, 509-516. Kamemoto F. I. (1964) The influence of the brain on osmotic and ionic regulation in earthworms. Gen. Camp. Endocrinol. 4, 420-426. Kamemoto F. I., Spalding A. E. and Keister S. M. (1962) Ionic balance in blood and coelomic fluid of earthworms. Bial. Euft. 122, 228-23 1. Lawrence J. M., Graig J. V. and Clough D. (1972) The presence of a hyperglycemic factor in the suprapharyngeal ganglia of Lumbricus terrestris. Cen. Corn>. &ddcr&ol. 18, 260-267. Mangum C. P. and Johansen K. (I 975) The colloid osmotic pressure of invertebrate body fluid. J. e-up. &of. 63, 661-671. Oglesby L. C. (1970) Studies on the salt and water balance of Nereis diversicolor. I. Steady state temperature. Camp. Biochem. Physiol. 36, 449-466. Oglesby L. C. (1973) Salt and water balance in lugworms (Polychaeta: Arenicolidae), with special reference to Areniculu pact&a in Coos Bay, Oregon. Eiol. Bull. 145, 180-199. Oglesby L. C., Mangum C. P., Heacox L. E. and Ready N. E. (1982) Salt and water balance in the polychaete [email protected] sirens. Camp. Biochem. Physioi. 73A, 15-l 9. Prosser C. L. and Brown F. A. Jr. (1961) Comparutice Animal Physiology. Saunders, Philadelphia. Roots B. I. ( 1955) The water relations of earthworms. I. The activity of the nephrostome cilia of Lumhricus ferrestris L. and ~~~o~obophorueh~orot~ca Savigny, in relation to the concentration of the bathing medium. J. eq. Viol. 32, 765-774. Takeuchi N. (1980a) Effect of brain removal on the osmotic and ionic concentrations of the coelomic fluid of earthworms placed in soil and salt solutions. Camp. Biochem. Physiol. 67A, 347-352. Takeuchi N. (1980b) A possibility of elevation of the free amino acid level for the extra-cellular hy~rosmotic adaptation of the earthworm Eisenia &)etida (Sav.) to the concentrated external medium. Comp. Biochem. Physiol. 67A, 353-355.