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Effects of glucose, glucose-6-phosphate, and fructose-6-phosphate on the electrical activity in the ventromedial hypothalamus in rats
SHORT COMMUNICATIONS
429
Effects of glucose, glucose-6-phosphate, and fructose-6-phosphate on the electrical activity in the ventromedial hypothalamus in rats The ventromedial hypothalamus (VMH) is considered as a satiety centera,14,16,19 and Mayers lt-l:~ has postulated that such an area would have to monitor the energy changes or energy stores of an organism. More specifically, Mayers 11-1a has proposed that there are glucoreceptors in the VMH which are activated by glucose or glucose utilization. Although studies1,2,5,9,10,12 have generally supported the glucostatic mechanism, no previous study has investigated the possibility that some glycolytic product rather than glucose may be the substrate for EEG activation in the VMH. In fact, an integration of biochemicalT,8,15, electrophysiological 1,2,4 and behavioral 9, la evidence suggests that the compound which increases the activity of the VMH is one preceding fructose-6-phosphate (FRU-6-P) in the glycolytic pathway, namely glucose or glucose-6-phosphate (GLU-6-P). Since GLU-6-P has a relatively greater biochemical importance than glucose in neural metabolism, it was hypothesized that G LU6-P would be an adequate stimulus for producing increased EEG activity in the VMH. Six female hooded rats, each anesthetized by an intraperitoneal injection of urethane (1000 mg/kg), were implanted in the VMH (De Groot --5.8A, 0.7L, --3.0D) with a rnonopolar recording cannula (27 and 34 gauge) which permitted multiple chemical stimulations with crystalline compounds. All animals, while still anesthetized, were tested 1 h after surgery and at the same time of day. The experiment consisted of 3 stimulus conditions (glucose, GLU-6-P, FRU6-P) which were preceded by a control period. The control condition involved the lowering of an empty cannula down through the affixed guide shaft, whereas, for the stimulus conditions, the cannula contained a given crystalline compound. The possibility of sequential effects was controlled by varyingthe order of chemical stimulations. Each subject was randomly assigned to one of 6 possible stimulus sequences. The recording session consisted of an initial 15 rain control period followed by three 15 rain periods of chemical stimulation. At the end of a 15 rain recording period the cannula was removed, cleaned, and a different compound was tapped into its tip. The presence of a compound in the cannula was verified by microscopic examination prior to its insertion. The time interval from the end of one condition to the beginning of the next was 5 rain. The EEG was amplified by means of a Tektronix 2A61 differential amplifier (frequency response at 3 dB attenuation was 6-20 c/sec) and recorded on an Ampex SP300 F'M tape recorder. At a later time the analog data were digitized and subjected to an autospectral analysis by means of a Honeywell 1200 digital computer. Since EEG data typically show a decrease in amplitude as frequency increases, a plot of amplitude as a function of frequency generally results in a negatively accelerating decreasing function. Therefore, it was desired to detect peaks (or changes) of activity for a given frequency band which would deviate from the above mentioned phenomenon. These output data were converted to natural logarithms for the purpose of normalizing the data .7. This analysis permitted the data to be reduced to 2 measures : (1) changes in specific frequency activities, and (2) changes in overall peak activity. Brain,Research, 22 (1970)429-433
430
Sl[(}ltt' (:{)~,i'qi \l~ "til(}N--. 02.
VMH 1
VMH 2
VMH 3
[]
OO I
i
L]
-04-
~ -0.6-
E3FRu~-~ ~ "~ 0.4-
Y_
02-
0.0 ~
Glucose
VMH 5
VMH 4
I i
LH 1
.....
_ _
-0.21 - 0 4q
Fig. I. Total peak activity for all conditions compared to the control condition (abscissa). The units On(w)) are the natural logarithms of the power spectra (OzVWc/sec). Histological examination showed that 5 of the animals had proper cannula placement in the VMH, whereas for one the cannula was located in the lateral hypothalamus (LH). Since placement of a natural substrate into an organism will initiate its metabolism, the E E G activity might have been confounded as time progressed. Differential effects could have been produced as the initial substrate depleted and the concentration of its metabolites increased. A running average analysis of the E E G activity as a function of time clearly indicated that the first 5 rain after chemical stimulation most likely represented the true effects from the initial substrate which dissolved into the neural tissue. Therefore, all additional analyses were performed on the first 5 rain of data for each condition. The results of the total peak activity for all V M H subjects are shown in Fig. 1. The directional effects of the EEG produced by the chemical stimulation when compared to the control condition are impressively consistent for all VMH subjects. GLU-6-P always increased the total peak activity above the control levels, whereas glucose and FRU-6-P always produced a decrease in power. A single factor repeated measures analysis of variance indicated that there were significant (P :: 0.001) changes in total peak activity across conditions. The results of comparing the means of all conditions with the control using a D u n n e t r s t statistic 18 showed that GLU-6-P significantly (P < 0.05, one-tail) increased the total peak activity, whereas glucose significantly (P < 0.01, 2-tail) decreased the total peak activity in the VMH. F R U 6-P also showed considerable inhibition in the V M H but did not quite reach the critical t value (t obtained ~ 2.68, t (P < 0.05, 2-tail) -~ 2.72). Interestingly, the only changes in total activity for the single LH subject was a decrease for the FRU-6-P condition. Brain Research, 22 (1970)429-433
431
sHORT COMMUNICATIONS
7.4-
7.3.
7.2
Z1
7£) ~ £o i
3 tO
6.9" /, t
68.
i' I
I
I
I
I
A(
6:5
616
6:7
FRU-6-P
618
69
7!0
activity
Fig. 2. A plot of total peak activity for GLU-6-P as a function of total peak activity for FRU-6-P. Units are in terms of natural logarithms of the total power of the spectra ((/~V)2/c/sec).
o ~~'... .
6.0 -
6.0-
= 5.0>,
~
~ 4,0D-
4.0-
•
3.0
,
6:,4-8.0
o GW-6-P • FRU-6-P • GlucoSe , Control
Control
i 9.6-11.2
i 12.8-14,4
Frequency
(Hz)
I 16.0-17.6
,
3.0
192-20.8
I
6.4-8.0 B
i 96-112
i 12.8-14.4
Frequency
I 160-17.6
'
19.2-20.8
(Hz)
Fig. 3. A, Autospectral analysis for all VMH subjects. (w) is proportional to the units of (ffV)e/ c/sec). B, Autospectral analysis for LH subject. (w) is proportional to the units of (ffV)"-/c/sec).
When the total peak activity of GLU-6-P was plotted as a function of total peak activity of FRU-6-P for all VMH subjects a linear relationship was found. A least squares analysis of the points yielded a line with a slope of 1.06 and is shown in Fig. 2. Fig. 3A depicts the mean results of the autospectral analyses for all VMH Brain Research, 22 (1970) 429-433
432
SH()R 1 ~ (~,l?~tt
~,.i~ \ i 1~ i ~
subjects for all conditions, whereas Fig. 3B shows the results f~,r ~hc ~ngie l~ii subject. It is apparent for the VMH subjects that the 6.4--8.0 c/see bar,J .A~t~tlffcctc~i to a greater extent than the other frequency bands. A repeated meast~'e~ ~!al).~i~ ~ variance verified that the only band width which contained sigT~ifica~t f/' !).()()[? changes was that of 6.4-8.0 c/sec. Comparing the means of all co~dili(,r~ wilh l!w control using Dunnett's t statistic demonstrated that GLU-6-P signific~tl) iP 0.05, one-tail) increased the peak activity of the 6.4 -8.0 c/see band. wi~¢reas bot!~ FRU-6-P (P ~. 0.02. 2-tail) and glucose (P :i 0.01, 2-tail) produced sig~i~itit:aJ~ decreases. All substrates for the LH subject produced decreases in aclivi!3 ~ the (~.4 8.0 c/see band. It should be noted that glucose and FRU-6-P prodtJ~'ed ~t greater inhibition than did GLU-6-P. A mechanism of activation in the VMH cannot be completel~ eit~cidated at this time. However, it appears that the VMH is selectively sensiti~e t~, GLU-6-1' and the increased activation results from either its presence and/or its J~letabl)lisr~. Fig. 2 shows that there is not only a one-to-one relationship betv~een the excitation produced by GLU-6-P and the inhibition produced by F R U - ~ , - P ~ f)t.iI ala<~ the extrapolation of this line passes through the origin. This suggests the possibility that the active equilibria between these two substrates are important to the ~aature of the electrical activity in the VMH. However, this does not eliminate the possibility that GLU-6-P may selectively interact with specific cells in the VMH suct~ that the electrical activity is increased, This possibility is strengthened by the resuh~ from the single LH subject. In this case, GLtJ-6-P had a negligible affect o~ the ~,otal peak activity, but caused considerable inhibition lk)r the 6.4 8.0 c/sec band. Thi> was the opposite effect found in the VMH and therefore indicates that similar ~ubstrates have selective effects in different cells. Biochemically, the latter appears more feasible at present since metabolic pathways and energy relationships essentially rcm~in similar from cell to cell. An inhibitory effect in the LH produced by GLU-6-P does fit well intt~ the presently known mechanisms of feeding behavior. An extremely sensitive mecha~fism would result if the same substrate which activates the 'satiety center" could simultane-ously inhibit the 'feeding center'. It has been demonstrated that there are direct neural connections between the VMH and LH ~, and that the electrical ~tctivity is suppressed in the LH when activity is high in the VMH ~. A combinatioH <~f direct neural inhibition in the LH by the VMH in conjunction with a biochemical inhibition by GLU-6-P would lead to an extremely sensitive mechanism controlling the activity in the LH. In conclusion, this study suggests an increased need for further studies concerning the neurochemical mechanisms of satiety and hunger. Studies such as stimulating the VMH and LH with specific substrates while the enzymes necessar~ for their metabolism are inhibited would elucidate if changes of activation arc due primarily to the presence of a given substrate or the changes in energy resulting t¥om its metabolism. In addition, it has to be demonstrated if these substrates wilt affect an al~irnal's feeding behavior in the predicted direction, i , e . . will GLU-6-P inhibit feeding and would glucose and FRU-6-P increase feeding. Brain Research,
22 (1970) 429-433
SItORT COMMUNICA.TIONS
433
This report is based on a thesis submitted in partial fulfillment of the requirements for the M.A. Degree from San Diego State College. The author wishes to thank Dr. Gary C. Galbraith for his support and assistance during the execution of this research. This investigation was supported by Public Health Service Research Grant MH-08667 from the National Institute of Mental Health, Department of Health, Education, and Welfare, and Public Health Service general research support Grant 1-S01-FR-05632-02, from the Department of Health, Education, and Welfare. Claremont Graduate School, and Department of Mental Hygiene, Pacific State Hospital, Pomona, Calif. 91766 (U.S.A.)
J. B. G L I D D O N
I ANAND, B. K., CHHINI, G. S., SHARMA, K. N., DUA, S., AND SINGH, B., Activity of single neurons in the hypothalamic feeding centers. Effect of glucose, Amer. J. Physiol., 207 (1964) 1146-1154. 2 ANAND, B. K., CHHINA, G. S., AND SINGH, B., Effect of glucose on the activity of hypothalamic feeding centers, Science, 138 (1962) 597-598. 3 A~;AND, B. K., DUA, S., AND SCHOENBERG,K., Hypothalamic control of food intake in cats and monkeys, J. Physiol. (Lond.), 127 (1955) 143-152. 4 ANAND, B. K., DUA, S., AND SINGH, B., Electrical activity of the hypothalamic feeding centers under the effect of changes in blood checnistry, Electroenceph. clin. Neurophysiol., 13 (1961) 54-59. 5 ANAND, B. K., TALWAR, C. P., DUA, S., AND MHATRE, R. M., Glucose and oxygen consumption of hypothalamic feeding centers, Ind. J. reed. Res., 49 (1961) 725-732. 6 AREES,E. A., AND MAYER, J., Anatomical connections between medial and lateral regions of the hypothalamus concerned with food intake, Science, 157 (1967) 1574-1575. 7 FmEDE, R. L., Topographic Brain Chemistry, Academic Press, New York, 1966, pp. 132-157. 8 FRUTON, J. S., ANt~ S1MMONDS,S., General Biochemistry, 3rd ed., Wiley, New York, 1961, pp. 402-544. 9 HERBERC3,L. J., Hunger reduction produced by injecting glucose into the lateral ventricle of the rat, Nature (Lond.), 187 (1960) 245-246. 10 HERBERG,L. J., Physiological drives investigated by means of injections into the cerebral ventricles of the rat, Quart. & exp. Psychol., 14 (1962) 8-14. 11 MAYER,J., G[ucostatic mechanisms of regulation of food intake, New Engl. J. Med., 249 (1953) 13-16. 12 MAYER, J., Regulation of energy intake and the body. The glucostatic theory and the lipostatic hypothesis, Ann. N. Y. Acad. Sci., 63 (1955) 15-43. 13 MAYER,J., AND MARSHALL, N. B., Specificity of goldthioglucose for ventromedial hypothalamic lesions and hyperphagia, Nature (Lond.), 178 (1956) 139%1400. 14 MAYER,J., ANt3THOMAS,D., Regulation of food intake and obesity, Science, 156 (1957) 328-337. 15 MCILWAIN, H., Biochemistry and the Central Nervous" System, 3rd ed., Little, Brown and Co., Boston, 1966, pp. 78-101. 16 TEITEI.BAUM, P., Disturbances in feeding and drinking behavior after hypothalamic lesions. In M. R. JONES (Ed.), Nebraska Symposiunt on Motivation, University of Nebraska Press, Lincoln, 196l, pp. 39-69. 17 WAI,TER, D. O., AND BRAZIER, M. A. B., Advances in LEG analysis, Electroenceph. elin. Neurophysiol., Suppl. 27 (1968) 13-18. 18 WINER, B. J., Statistical Principles in Experimental Design, McGraw-Hill, New York, 1962, pp. 89 92. 19 WYRW~CKA,W., AND DOBRZECKA,C., Relationship between feeding and satiation centers of the hypothalamus, Scienee, 123 (1960) 805-806.
(Accepted June 15th, 1970)
Brain Research, 22 (1970)429-433
429
Effects of glucose, glucose-6-phosphate, and fructose-6-phosphate on the electrical activity in the ventromedial hypothalamus in rats The ventromedial hypothalamus (VMH) is considered as a satiety centera,14,16,19 and Mayers lt-l:~ has postulated that such an area would have to monitor the energy changes or energy stores of an organism. More specifically, Mayers 11-1a has proposed that there are glucoreceptors in the VMH which are activated by glucose or glucose utilization. Although studies1,2,5,9,10,12 have generally supported the glucostatic mechanism, no previous study has investigated the possibility that some glycolytic product rather than glucose may be the substrate for EEG activation in the VMH. In fact, an integration of biochemicalT,8,15, electrophysiological 1,2,4 and behavioral 9, la evidence suggests that the compound which increases the activity of the VMH is one preceding fructose-6-phosphate (FRU-6-P) in the glycolytic pathway, namely glucose or glucose-6-phosphate (GLU-6-P). Since GLU-6-P has a relatively greater biochemical importance than glucose in neural metabolism, it was hypothesized that G LU6-P would be an adequate stimulus for producing increased EEG activity in the VMH. Six female hooded rats, each anesthetized by an intraperitoneal injection of urethane (1000 mg/kg), were implanted in the VMH (De Groot --5.8A, 0.7L, --3.0D) with a rnonopolar recording cannula (27 and 34 gauge) which permitted multiple chemical stimulations with crystalline compounds. All animals, while still anesthetized, were tested 1 h after surgery and at the same time of day. The experiment consisted of 3 stimulus conditions (glucose, GLU-6-P, FRU6-P) which were preceded by a control period. The control condition involved the lowering of an empty cannula down through the affixed guide shaft, whereas, for the stimulus conditions, the cannula contained a given crystalline compound. The possibility of sequential effects was controlled by varyingthe order of chemical stimulations. Each subject was randomly assigned to one of 6 possible stimulus sequences. The recording session consisted of an initial 15 rain control period followed by three 15 rain periods of chemical stimulation. At the end of a 15 rain recording period the cannula was removed, cleaned, and a different compound was tapped into its tip. The presence of a compound in the cannula was verified by microscopic examination prior to its insertion. The time interval from the end of one condition to the beginning of the next was 5 rain. The EEG was amplified by means of a Tektronix 2A61 differential amplifier (frequency response at 3 dB attenuation was 6-20 c/sec) and recorded on an Ampex SP300 F'M tape recorder. At a later time the analog data were digitized and subjected to an autospectral analysis by means of a Honeywell 1200 digital computer. Since EEG data typically show a decrease in amplitude as frequency increases, a plot of amplitude as a function of frequency generally results in a negatively accelerating decreasing function. Therefore, it was desired to detect peaks (or changes) of activity for a given frequency band which would deviate from the above mentioned phenomenon. These output data were converted to natural logarithms for the purpose of normalizing the data .7. This analysis permitted the data to be reduced to 2 measures : (1) changes in specific frequency activities, and (2) changes in overall peak activity. Brain,Research, 22 (1970)429-433
430
Sl[(}ltt' (:{)~,i'qi \l~ "til(}N--. 02.
VMH 1
VMH 2
VMH 3
[]
OO I
i
L]
-04-
~ -0.6-
E3FRu~-~ ~ "~ 0.4-
Y_
02-
0.0 ~
Glucose
VMH 5
VMH 4
I i
LH 1
.....
_ _
-0.21 - 0 4q
Fig. I. Total peak activity for all conditions compared to the control condition (abscissa). The units On(w)) are the natural logarithms of the power spectra (OzVWc/sec). Histological examination showed that 5 of the animals had proper cannula placement in the VMH, whereas for one the cannula was located in the lateral hypothalamus (LH). Since placement of a natural substrate into an organism will initiate its metabolism, the E E G activity might have been confounded as time progressed. Differential effects could have been produced as the initial substrate depleted and the concentration of its metabolites increased. A running average analysis of the E E G activity as a function of time clearly indicated that the first 5 rain after chemical stimulation most likely represented the true effects from the initial substrate which dissolved into the neural tissue. Therefore, all additional analyses were performed on the first 5 rain of data for each condition. The results of the total peak activity for all V M H subjects are shown in Fig. 1. The directional effects of the EEG produced by the chemical stimulation when compared to the control condition are impressively consistent for all VMH subjects. GLU-6-P always increased the total peak activity above the control levels, whereas glucose and FRU-6-P always produced a decrease in power. A single factor repeated measures analysis of variance indicated that there were significant (P :: 0.001) changes in total peak activity across conditions. The results of comparing the means of all conditions with the control using a D u n n e t r s t statistic 18 showed that GLU-6-P significantly (P < 0.05, one-tail) increased the total peak activity, whereas glucose significantly (P < 0.01, 2-tail) decreased the total peak activity in the VMH. F R U 6-P also showed considerable inhibition in the V M H but did not quite reach the critical t value (t obtained ~ 2.68, t (P < 0.05, 2-tail) -~ 2.72). Interestingly, the only changes in total activity for the single LH subject was a decrease for the FRU-6-P condition. Brain Research, 22 (1970)429-433
431
sHORT COMMUNICATIONS
7.4-
7.3.
7.2
Z1
7£) ~ £o i
3 tO
6.9" /, t
68.
i' I
I
I
I
I
A(
6:5
616
6:7
FRU-6-P
618
69
7!0
activity
Fig. 2. A plot of total peak activity for GLU-6-P as a function of total peak activity for FRU-6-P. Units are in terms of natural logarithms of the total power of the spectra ((/~V)2/c/sec).
o ~~'... .
6.0 -
6.0-
= 5.0>,
~
~ 4,0D-
4.0-
•
3.0
,
6:,4-8.0
o GW-6-P • FRU-6-P • GlucoSe , Control
Control
i 9.6-11.2
i 12.8-14,4
Frequency
(Hz)
I 16.0-17.6
,
3.0
192-20.8
I
6.4-8.0 B
i 96-112
i 12.8-14.4
Frequency
I 160-17.6
'
19.2-20.8
(Hz)
Fig. 3. A, Autospectral analysis for all VMH subjects. (w) is proportional to the units of (ffV)e/ c/sec). B, Autospectral analysis for LH subject. (w) is proportional to the units of (ffV)"-/c/sec).
When the total peak activity of GLU-6-P was plotted as a function of total peak activity of FRU-6-P for all VMH subjects a linear relationship was found. A least squares analysis of the points yielded a line with a slope of 1.06 and is shown in Fig. 2. Fig. 3A depicts the mean results of the autospectral analyses for all VMH Brain Research, 22 (1970) 429-433
432
SH()R 1 ~ (~,l?~tt
~,.i~ \ i 1~ i ~
subjects for all conditions, whereas Fig. 3B shows the results f~,r ~hc ~ngie l~ii subject. It is apparent for the VMH subjects that the 6.4--8.0 c/see bar,J .A~t~tlffcctc~i to a greater extent than the other frequency bands. A repeated meast~'e~ ~!al).~i~ ~ variance verified that the only band width which contained sigT~ifica~t f/' !).()()[? changes was that of 6.4-8.0 c/sec. Comparing the means of all co~dili(,r~ wilh l!w control using Dunnett's t statistic demonstrated that GLU-6-P signific~tl) iP 0.05, one-tail) increased the peak activity of the 6.4 -8.0 c/see band. wi~¢reas bot!~ FRU-6-P (P ~. 0.02. 2-tail) and glucose (P :i 0.01, 2-tail) produced sig~i~itit:aJ~ decreases. All substrates for the LH subject produced decreases in aclivi!3 ~ the (~.4 8.0 c/see band. It should be noted that glucose and FRU-6-P prodtJ~'ed ~t greater inhibition than did GLU-6-P. A mechanism of activation in the VMH cannot be completel~ eit~cidated at this time. However, it appears that the VMH is selectively sensiti~e t~, GLU-6-1' and the increased activation results from either its presence and/or its J~letabl)lisr~. Fig. 2 shows that there is not only a one-to-one relationship betv~een the excitation produced by GLU-6-P and the inhibition produced by F R U - ~ , - P ~ f)t.iI ala<~ the extrapolation of this line passes through the origin. This suggests the possibility that the active equilibria between these two substrates are important to the ~aature of the electrical activity in the VMH. However, this does not eliminate the possibility that GLU-6-P may selectively interact with specific cells in the VMH suct~ that the electrical activity is increased, This possibility is strengthened by the resuh~ from the single LH subject. In this case, GLtJ-6-P had a negligible affect o~ the ~,otal peak activity, but caused considerable inhibition lk)r the 6.4 8.0 c/sec band. Thi> was the opposite effect found in the VMH and therefore indicates that similar ~ubstrates have selective effects in different cells. Biochemically, the latter appears more feasible at present since metabolic pathways and energy relationships essentially rcm~in similar from cell to cell. An inhibitory effect in the LH produced by GLU-6-P does fit well intt~ the presently known mechanisms of feeding behavior. An extremely sensitive mecha~fism would result if the same substrate which activates the 'satiety center" could simultane-ously inhibit the 'feeding center'. It has been demonstrated that there are direct neural connections between the VMH and LH ~, and that the electrical ~tctivity is suppressed in the LH when activity is high in the VMH ~. A combinatioH <~f direct neural inhibition in the LH by the VMH in conjunction with a biochemical inhibition by GLU-6-P would lead to an extremely sensitive mechanism controlling the activity in the LH. In conclusion, this study suggests an increased need for further studies concerning the neurochemical mechanisms of satiety and hunger. Studies such as stimulating the VMH and LH with specific substrates while the enzymes necessar~ for their metabolism are inhibited would elucidate if changes of activation arc due primarily to the presence of a given substrate or the changes in energy resulting t¥om its metabolism. In addition, it has to be demonstrated if these substrates wilt affect an al~irnal's feeding behavior in the predicted direction, i , e . . will GLU-6-P inhibit feeding and would glucose and FRU-6-P increase feeding. Brain Research,
22 (1970) 429-433
SItORT COMMUNICA.TIONS
433
This report is based on a thesis submitted in partial fulfillment of the requirements for the M.A. Degree from San Diego State College. The author wishes to thank Dr. Gary C. Galbraith for his support and assistance during the execution of this research. This investigation was supported by Public Health Service Research Grant MH-08667 from the National Institute of Mental Health, Department of Health, Education, and Welfare, and Public Health Service general research support Grant 1-S01-FR-05632-02, from the Department of Health, Education, and Welfare. Claremont Graduate School, and Department of Mental Hygiene, Pacific State Hospital, Pomona, Calif. 91766 (U.S.A.)
J. B. G L I D D O N
I ANAND, B. K., CHHINI, G. S., SHARMA, K. N., DUA, S., AND SINGH, B., Activity of single neurons in the hypothalamic feeding centers. Effect of glucose, Amer. J. Physiol., 207 (1964) 1146-1154. 2 ANAND, B. K., CHHINA, G. S., AND SINGH, B., Effect of glucose on the activity of hypothalamic feeding centers, Science, 138 (1962) 597-598. 3 A~;AND, B. K., DUA, S., AND SCHOENBERG,K., Hypothalamic control of food intake in cats and monkeys, J. Physiol. (Lond.), 127 (1955) 143-152. 4 ANAND, B. K., DUA, S., AND SINGH, B., Electrical activity of the hypothalamic feeding centers under the effect of changes in blood checnistry, Electroenceph. clin. Neurophysiol., 13 (1961) 54-59. 5 ANAND, B. K., TALWAR, C. P., DUA, S., AND MHATRE, R. M., Glucose and oxygen consumption of hypothalamic feeding centers, Ind. J. reed. Res., 49 (1961) 725-732. 6 AREES,E. A., AND MAYER, J., Anatomical connections between medial and lateral regions of the hypothalamus concerned with food intake, Science, 157 (1967) 1574-1575. 7 FmEDE, R. L., Topographic Brain Chemistry, Academic Press, New York, 1966, pp. 132-157. 8 FRUTON, J. S., ANt~ S1MMONDS,S., General Biochemistry, 3rd ed., Wiley, New York, 1961, pp. 402-544. 9 HERBERC3,L. J., Hunger reduction produced by injecting glucose into the lateral ventricle of the rat, Nature (Lond.), 187 (1960) 245-246. 10 HERBERG,L. J., Physiological drives investigated by means of injections into the cerebral ventricles of the rat, Quart. & exp. Psychol., 14 (1962) 8-14. 11 MAYER,J., G[ucostatic mechanisms of regulation of food intake, New Engl. J. Med., 249 (1953) 13-16. 12 MAYER, J., Regulation of energy intake and the body. The glucostatic theory and the lipostatic hypothesis, Ann. N. Y. Acad. Sci., 63 (1955) 15-43. 13 MAYER,J., AND MARSHALL, N. B., Specificity of goldthioglucose for ventromedial hypothalamic lesions and hyperphagia, Nature (Lond.), 178 (1956) 139%1400. 14 MAYER,J., ANt3THOMAS,D., Regulation of food intake and obesity, Science, 156 (1957) 328-337. 15 MCILWAIN, H., Biochemistry and the Central Nervous" System, 3rd ed., Little, Brown and Co., Boston, 1966, pp. 78-101. 16 TEITEI.BAUM, P., Disturbances in feeding and drinking behavior after hypothalamic lesions. In M. R. JONES (Ed.), Nebraska Symposiunt on Motivation, University of Nebraska Press, Lincoln, 196l, pp. 39-69. 17 WAI,TER, D. O., AND BRAZIER, M. A. B., Advances in LEG analysis, Electroenceph. elin. Neurophysiol., Suppl. 27 (1968) 13-18. 18 WINER, B. J., Statistical Principles in Experimental Design, McGraw-Hill, New York, 1962, pp. 89 92. 19 WYRW~CKA,W., AND DOBRZECKA,C., Relationship between feeding and satiation centers of the hypothalamus, Scienee, 123 (1960) 805-806.
(Accepted June 15th, 1970)
Brain Research, 22 (1970)429-433