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CMS temperature sensitivity during the hibernation cycle in the 13-lined ground squirrel
100 POSTER
Abstracts--Strateqtes m cold PRESENTATIONS
TF2~PERATURE-SENSITIVITY OF ~XONAL TRANSPORT IN HIBERNATORS &ND NON-HIBErNATORS. M.A Bisbv and D.L. Jones. Division of Medical Physiology, Unlversitv of Calgary, Alberta. Skeletal muscle of hibernating mammals is trophically matntalned by nerves even at bed, temperatures as low as 5°C. In these animals conduction of action potentials in peripheral nerves occurs 2t thls temperature, whereas in non-hlbernators conduction is blocked We have investigated the temperature-sensltivlty of axonal transport to see if thls second form of axonal con~nunicatlon, thought to be involved in trophlc control of muscle, is also modified in hibernators Sprague-Dawlev rats and ground squirrels (Sper~oph{ ~u8 P P~O'~a2P~80~) were used. Hxbernatlng ground squlrrels (rectal temperature ! 7~C ) were warmed to 37"C over a two hour period immediately be fore use. 3H_L proline was injected into the L5 dorsal root ganglia and after allowing two hours for labeled protein to enter the sensory axons the sciatic nerves were removed. One nerve was in=nedlately frozen while the other was incubated ~n oxygenated Ringer's solution for a known time at a known temperature and then frozen. The frozen nerves were cut into 2mm segments and assayed for labeled protein so that a profile of activity in the sciatic nerves could be constructed. Velocity of transport was calculated from the difference in position of the wave front of transported proteins in the two nerves, divided bv the duratlon of incubation. In both rats and ground squirrels transport stopped below 10=C. Between 15"C and 38"C velocity (V) mm/hr was related to temperature (t) thus for rats, V=.292 (i.ii0) t, for ground squirrels V=.393(i.i02) t. There was no significant dlfference in slope or intercept of the regression llnes for log V x t. Results from 5 h~bernatlng ground squirrels were within the range for the other animals. We conclude that axonal transport is not modified in the peripheral nerves of thls hibernating species, so it is likely that axonal transport is not responsible for the trophlc maintenance of muscle in hibernating mammals with a body temperature below 10°C. (Supported b~ the University of Calgary Grants Cormmlttee and tile ,%fRC)
S.~mpomum
Most m i c e a t 31"C e m e r g e d a t n e a r l y t h e s a m e t l n e ~ . t h i a r ~ portions of their seed supplies uneaten, but m~'e at 8°C ~nd 16"C remained continuously underground for up t~ two velrs until their energy reserves were exhausted Tnu~, at l,~w temperatures, the duration of the underground phase o~ behavior depends upon the amount of food stored and the rate It Is consumed The amount of time the mt~e are torpid influences their rate of food consumption. ~nd, consequently, the period of their behavlora] cycle The ch~n~es in behavior are best described by an hour-~la~s model, ~nd ~n endogenous clrcannual oscillltor need n,~t he evoked
THE RESPONSE OF COLD SENSITIVE GOLDEN SPI',I MOLSE (d~;~':7 A. }lalm and A Borat Lniversltv of Haifa, The School of Education of the kibbutz Movement, Oranlm. P O. kiryat Tivon, Israel. The Golden Spiny Mouse A29~38 russets3, Is limited in its distribution to extremely hot environments of the Rift Valley An exception to this pattern is a population inhabiting the high mountains of SoutherP Sinai (above 200~n) which are annualy covered with snow and where low temperatures occur every winter Specimens of this species inhabiting hot habitats close to the Dead Sea shore (E G population) were found to be cold sensitive (Shkolnik and Borut, 1969), while individuals inhabiting the high mountains of Southern Sinai (S-population) are cold resistant (Haim and gorut, 1974) Nonshlvering thermogenesls plays an important role in adaptation of S-mlce to cold environments E G.- indlvlduals acclimated at Ta=28°C and treated with high dosage of thyroxine became cold resistant (Balm and Borut, 1976~ This stud~ examlnes the response of E G - mice to a treatment of melatonln Cold sensitive E G - female mice acclimated at Ia=28°C ani treated wlth a dally injection of melatonzn (img/kg BW) for three weeks, became cold resistant when exposed to Ta=6°C for six hours All melatonin treated individuals lost 10% of their body weight on average These mice showed a high response to norep~nepbrine and ~ncreased their oxygen consumption 5 times on average above the resting level The increase in oxygen consumption was accompanled by a significant ~ncrease in rectal temperature From these results it may be assumed that the pineal body has a function in the rmoregulation of the golden splnv mouse. The response to melatontn may be due to an increase in thvrold activity or hypertrophy of brown, fat as ~as HIBERNATION AS A BIOLO(,ILAL qOOEL FOrt ~NIC-DEPRES%IVE ILLinvestigated by Heldmaler and Hoffmann (io~4~ and L~n h anJ NESS' PILOT STUDIES Jav R Feierman,l, 2 Frlc T Pengelley 3, Epstein (1976) Arnold J. Mandell I, Suzanne knapp 1 Lack of suitable blologlcal models have been a major problem in p s y c h i a t r i c research. In t h e f i r s t of a s e r ~ e s o f C,,S T E q P E ~ T L R F SFNqlTIVITI DURING THF I ~ I Z T R N ~ I I O , , , r r controlled pilot studies designed to test the utility of the Ih ThE 13-LINED GROUND ~OUIRREI W.C q a r t n c r , Den~rtmodel, the cxrcannual torpldltv in ~ . t ~ a ~t~'i~o was ment o f P h y s i o l o g y and B i o p h y s i c s , L q l v e r s l t v of l l l l n o l s . significantly reduced by imlpramxne IICI, a drug used to treat U r b a n a , IL and D e p a r t m e n t o f B i o l o g y , " , o r t h e a s t e r n l p l - e r the depressed phase of manlc-depresstve Illness. A series of s l t y , g o s t o n , ' M A 0 2 1 1 5 , UqA. eight electrlcally induced convulsions prior to torpidity The role plaved by the preoptic-anterlor l,ypothala-lus had no effect on subsequent torpidltv, however Further in temperature responsiveness durln~ the blbernatlon cvcle tests of the model being planned are discussed. Concurrent was examined with animals (Gq) prepared for contlnuou~ with the above tests of the model, tryptoph~n bvdroxylase c h r o n i c r e c o r d i n g o f T p o a h , Ts, 1 n, ~.IG and ,lR A uat.r activity was investigated in regional areas of the brain perfusagle thermooe was i m p l a n t e d ~Ilthin t a e POA'I ( F r t during torpidity. A marked reduction of enzyme activity was optic-anterlor hypothalamu~) Tpoah was ~anlpulated during found in the torpid versus aroused controls. Calcium all phases of the hibernation cyr'o P~AF tlermosensltlVltV activated the enzyme ~ N~trO, but showed no correlation with %as determined during the euthermic phase and compared in enzyme actlvltv bn Uzuo the results are discussed in terms the same GS in spring by calculatlor o f • #mr met~bollsm of testable hypotheses for the neuroregulatorv mechanisms using 02 consumption data. Th*' wimter ra,~e o f ~ ( " " g - " °Cunderlying torpidity and applicability o f the model to an equaled 0.68 to 1.3B the sprln~ range ~as 1.96 to 2 7b ethological paradigm for manlc-depresslve Illness is (Values are duplicate determlnatlons on ? anlmals) Durln~ presented. nibernatlon entry, the threshold for elevation of }q a-d i. Dept. of Psychiatry, Unlversztv of California, San D~ego, Tbody fell continuously. Deep hibernation ~,a~ ch~racter(La Jolla, Californla 92037) Ized by eltner a complete lack of POAW temperature Induced 2 Dept of Psychiatry, University of hew Mexico, increase of PR and EHG until arousal to Tpoah as io~ as (Albuquerque, New Mexico 87131) -i 5=C or by a decllnlnp responsiveness as hibernation 3 Dept of Biology, University of California, Riverside, proceeded until a few hours before an arousal. ~esD,~ns!ve (Riverside, California 92501) animals possessed a greater apparent eutnermlc phase * All GR aroused when challenged w|th a low Tat r The ENERGETIC LJNblRAINTS ON IHL ANNUAL CYCLE t)~ B-HA%It)R IN FHE following conclusions are suggested for |3-lined lie i) POAH thermoregulatory threshold tamp, rattlre decllles POCKET MOUSE, PEROGNATPUS LONGIJ~,'4BRIS Alan R F r e n c h progressively during hibernation entry and deep hlberDepartment of Biology, University of California, Los Angeles, nation It increases a few hours before fill arousals, CA 90024, USA. (Present address Department of Blologv, 2) Some type of temperature sensing is retained in Cq unUniversity of Californla, Riverside, CA 9252[, USA ) responsive to Tpoah manipulation during deep tlihernatlon The influence of energy supplies on the annual cycle of 3) Unresponsive animals may have an apparent lower surface-actlve and underground phases of behavlor was Alternatively, unresponsiveness is due to an evvn loser investigated in 38 pocket mice kept on a 12-hour photoperiod at 8"C, 16~C or 31"C. Each mouse constructed a burrow response threshold temperature 4) e appears to be greater in sprlng tqan 1 1 % I n t e r htt~een system in a dlrt-filled terrarium, and was fed one of several different rations of seeds The date the animals hibernation bouts (Supported in part by SF (,~ 13797) ceased foraging, the time they spent contlnuouslv underground, and the slze of thelr food stores upon emergence were measured Mice that were prevented from REWARMING RATES FROM TORPOR IN MAMMALS AND BIRDS Heldstoring food did not stop foraging, but animals that maier, G Zoologlscbes Institut, Unlverslt~t Frankfurt, inltially stored over tOO g of seeds later appeared to cease 6000 Frankfurt, BRD. surface activity spontaneously The timing of this action Rewarmlng rates from torpor are compared in more than was not dependent on either (1) ambient temperature, (It) 60 species of rodents, bats, insectivores, marsupials and the amount of food, above some minimum, Inltlallv stored, or birds The s p e e d of rewarming from torpor is negatively (lii) the daily foraging success. Low temperatures apparently inhibit the normal resumption of surface actlvltv. correlated with body weight, revealing similar slopes In
RUSSA20S) TO MELATONIN
)
Abstracts--Strateqtes m cold PRESENTATIONS
TF2~PERATURE-SENSITIVITY OF ~XONAL TRANSPORT IN HIBERNATORS &ND NON-HIBErNATORS. M.A Bisbv and D.L. Jones. Division of Medical Physiology, Unlversitv of Calgary, Alberta. Skeletal muscle of hibernating mammals is trophically matntalned by nerves even at bed, temperatures as low as 5°C. In these animals conduction of action potentials in peripheral nerves occurs 2t thls temperature, whereas in non-hlbernators conduction is blocked We have investigated the temperature-sensltivlty of axonal transport to see if thls second form of axonal con~nunicatlon, thought to be involved in trophlc control of muscle, is also modified in hibernators Sprague-Dawlev rats and ground squirrels (Sper~oph{ ~u8 P P~O'~a2P~80~) were used. Hxbernatlng ground squlrrels (rectal temperature ! 7~C ) were warmed to 37"C over a two hour period immediately be fore use. 3H_L proline was injected into the L5 dorsal root ganglia and after allowing two hours for labeled protein to enter the sensory axons the sciatic nerves were removed. One nerve was in=nedlately frozen while the other was incubated ~n oxygenated Ringer's solution for a known time at a known temperature and then frozen. The frozen nerves were cut into 2mm segments and assayed for labeled protein so that a profile of activity in the sciatic nerves could be constructed. Velocity of transport was calculated from the difference in position of the wave front of transported proteins in the two nerves, divided bv the duratlon of incubation. In both rats and ground squirrels transport stopped below 10=C. Between 15"C and 38"C velocity (V) mm/hr was related to temperature (t) thus for rats, V=.292 (i.ii0) t, for ground squirrels V=.393(i.i02) t. There was no significant dlfference in slope or intercept of the regression llnes for log V x t. Results from 5 h~bernatlng ground squirrels were within the range for the other animals. We conclude that axonal transport is not modified in the peripheral nerves of thls hibernating species, so it is likely that axonal transport is not responsible for the trophlc maintenance of muscle in hibernating mammals with a body temperature below 10°C. (Supported b~ the University of Calgary Grants Cormmlttee and tile ,%fRC)
S.~mpomum
Most m i c e a t 31"C e m e r g e d a t n e a r l y t h e s a m e t l n e ~ . t h i a r ~ portions of their seed supplies uneaten, but m~'e at 8°C ~nd 16"C remained continuously underground for up t~ two velrs until their energy reserves were exhausted Tnu~, at l,~w temperatures, the duration of the underground phase o~ behavior depends upon the amount of food stored and the rate It Is consumed The amount of time the mt~e are torpid influences their rate of food consumption. ~nd, consequently, the period of their behavlora] cycle The ch~n~es in behavior are best described by an hour-~la~s model, ~nd ~n endogenous clrcannual oscillltor need n,~t he evoked
THE RESPONSE OF COLD SENSITIVE GOLDEN SPI',I MOLSE (d~;~':7 A. }lalm and A Borat Lniversltv of Haifa, The School of Education of the kibbutz Movement, Oranlm. P O. kiryat Tivon, Israel. The Golden Spiny Mouse A29~38 russets3, Is limited in its distribution to extremely hot environments of the Rift Valley An exception to this pattern is a population inhabiting the high mountains of SoutherP Sinai (above 200~n) which are annualy covered with snow and where low temperatures occur every winter Specimens of this species inhabiting hot habitats close to the Dead Sea shore (E G population) were found to be cold sensitive (Shkolnik and Borut, 1969), while individuals inhabiting the high mountains of Southern Sinai (S-population) are cold resistant (Haim and gorut, 1974) Nonshlvering thermogenesls plays an important role in adaptation of S-mlce to cold environments E G.- indlvlduals acclimated at Ta=28°C and treated with high dosage of thyroxine became cold resistant (Balm and Borut, 1976~ This stud~ examlnes the response of E G - mice to a treatment of melatonln Cold sensitive E G - female mice acclimated at Ia=28°C ani treated wlth a dally injection of melatonzn (img/kg BW) for three weeks, became cold resistant when exposed to Ta=6°C for six hours All melatonin treated individuals lost 10% of their body weight on average These mice showed a high response to norep~nepbrine and ~ncreased their oxygen consumption 5 times on average above the resting level The increase in oxygen consumption was accompanled by a significant ~ncrease in rectal temperature From these results it may be assumed that the pineal body has a function in the rmoregulation of the golden splnv mouse. The response to melatontn may be due to an increase in thvrold activity or hypertrophy of brown, fat as ~as HIBERNATION AS A BIOLO(,ILAL qOOEL FOrt ~NIC-DEPRES%IVE ILLinvestigated by Heldmaler and Hoffmann (io~4~ and L~n h anJ NESS' PILOT STUDIES Jav R Feierman,l, 2 Frlc T Pengelley 3, Epstein (1976) Arnold J. Mandell I, Suzanne knapp 1 Lack of suitable blologlcal models have been a major problem in p s y c h i a t r i c research. In t h e f i r s t of a s e r ~ e s o f C,,S T E q P E ~ T L R F SFNqlTIVITI DURING THF I ~ I Z T R N ~ I I O , , , r r controlled pilot studies designed to test the utility of the Ih ThE 13-LINED GROUND ~OUIRREI W.C q a r t n c r , Den~rtmodel, the cxrcannual torpldltv in ~ . t ~ a ~t~'i~o was ment o f P h y s i o l o g y and B i o p h y s i c s , L q l v e r s l t v of l l l l n o l s . significantly reduced by imlpramxne IICI, a drug used to treat U r b a n a , IL and D e p a r t m e n t o f B i o l o g y , " , o r t h e a s t e r n l p l - e r the depressed phase of manlc-depresstve Illness. A series of s l t y , g o s t o n , ' M A 0 2 1 1 5 , UqA. eight electrlcally induced convulsions prior to torpidity The role plaved by the preoptic-anterlor l,ypothala-lus had no effect on subsequent torpidltv, however Further in temperature responsiveness durln~ the blbernatlon cvcle tests of the model being planned are discussed. Concurrent was examined with animals (Gq) prepared for contlnuou~ with the above tests of the model, tryptoph~n bvdroxylase c h r o n i c r e c o r d i n g o f T p o a h , Ts, 1 n, ~.IG and ,lR A uat.r activity was investigated in regional areas of the brain perfusagle thermooe was i m p l a n t e d ~Ilthin t a e POA'I ( F r t during torpidity. A marked reduction of enzyme activity was optic-anterlor hypothalamu~) Tpoah was ~anlpulated during found in the torpid versus aroused controls. Calcium all phases of the hibernation cyr'o P~AF tlermosensltlVltV activated the enzyme ~ N~trO, but showed no correlation with %as determined during the euthermic phase and compared in enzyme actlvltv bn Uzuo the results are discussed in terms the same GS in spring by calculatlor o f • #mr met~bollsm of testable hypotheses for the neuroregulatorv mechanisms using 02 consumption data. Th*' wimter ra,~e o f ~ ( " " g - " °Cunderlying torpidity and applicability o f the model to an equaled 0.68 to 1.3B the sprln~ range ~as 1.96 to 2 7b ethological paradigm for manlc-depresslve Illness is (Values are duplicate determlnatlons on ? anlmals) Durln~ presented. nibernatlon entry, the threshold for elevation of }q a-d i. Dept. of Psychiatry, Unlversztv of California, San D~ego, Tbody fell continuously. Deep hibernation ~,a~ ch~racter(La Jolla, Californla 92037) Ized by eltner a complete lack of POAW temperature Induced 2 Dept of Psychiatry, University of hew Mexico, increase of PR and EHG until arousal to Tpoah as io~ as (Albuquerque, New Mexico 87131) -i 5=C or by a decllnlnp responsiveness as hibernation 3 Dept of Biology, University of California, Riverside, proceeded until a few hours before an arousal. ~esD,~ns!ve (Riverside, California 92501) animals possessed a greater apparent eutnermlc phase * All GR aroused when challenged w|th a low Tat r The ENERGETIC LJNblRAINTS ON IHL ANNUAL CYCLE t)~ B-HA%It)R IN FHE following conclusions are suggested for |3-lined lie i) POAH thermoregulatory threshold tamp, rattlre decllles POCKET MOUSE, PEROGNATPUS LONGIJ~,'4BRIS Alan R F r e n c h progressively during hibernation entry and deep hlberDepartment of Biology, University of California, Los Angeles, nation It increases a few hours before fill arousals, CA 90024, USA. (Present address Department of Blologv, 2) Some type of temperature sensing is retained in Cq unUniversity of Californla, Riverside, CA 9252[, USA ) responsive to Tpoah manipulation during deep tlihernatlon The influence of energy supplies on the annual cycle of 3) Unresponsive animals may have an apparent lower surface-actlve and underground phases of behavlor was Alternatively, unresponsiveness is due to an evvn loser investigated in 38 pocket mice kept on a 12-hour photoperiod at 8"C, 16~C or 31"C. Each mouse constructed a burrow response threshold temperature 4) e appears to be greater in sprlng tqan 1 1 % I n t e r htt~een system in a dlrt-filled terrarium, and was fed one of several different rations of seeds The date the animals hibernation bouts (Supported in part by SF (,~ 13797) ceased foraging, the time they spent contlnuouslv underground, and the slze of thelr food stores upon emergence were measured Mice that were prevented from REWARMING RATES FROM TORPOR IN MAMMALS AND BIRDS Heldstoring food did not stop foraging, but animals that maier, G Zoologlscbes Institut, Unlverslt~t Frankfurt, inltially stored over tOO g of seeds later appeared to cease 6000 Frankfurt, BRD. surface activity spontaneously The timing of this action Rewarmlng rates from torpor are compared in more than was not dependent on either (1) ambient temperature, (It) 60 species of rodents, bats, insectivores, marsupials and the amount of food, above some minimum, Inltlallv stored, or birds The s p e e d of rewarming from torpor is negatively (lii) the daily foraging success. Low temperatures apparently inhibit the normal resumption of surface actlvltv. correlated with body weight, revealing similar slopes In
RUSSA20S) TO MELATONIN
)