| Co-Investigator(Kenkyū-buntansha) |
OMOTO Mikiko , 助手 (20309636)
TAMURA Yutaka Fukuyama University, Faculty of Pharmacy and pharmaceutical Sciences, Assistant Professor, 薬学部, 助教授 (30217202)
NAKAMURA Akiriro Fukuyama University, Faculty of Pharmacy and pharmaceutical Sciences, Professor, 薬学部, 教授 (70172393)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2001: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Research Abstract |
It is known that golden hamster hibernates in cold environment. The hibernation of the hamster is classified into entrance stage, maintenance stage and arousal stage. In entrance stage, the body temperature (B.T.) of hamster lowers to almost environmental temperature, and the lowered B.T. continues in maintenance stage. Intracerebroventricular (i.c.v.) administrations of adenosine (ADO) and ATP produced hypothermia in hamster. The hypothermia produced by ADO and ATP suppressed by CPT, an adenosine A1 receptor antagonist. Moreover, i.c.v. administrated CHA, an adenosine A1 receptor agonist, lowered the B.T. to almost environmental temperature. I.c.v. administrated β-endorphin produced hypothermia in a dose-dependent manner. DAMGO, a selective μ-receptor agonist, also lowered the B.T. to almost environmental temperature. In entrance stage, administration (i.c.v.) of CPT produced uprise of the B.T., but did not in maintenance stage. Administration of naloxone in maintenance stage produced
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uprise of the B.T., but did not in entrance stage. The A1 receptor number of the hypothalamus in entrance stage decreased. These results suggest that adenosine regulates the B.T. of hamster in entrance stage via A1 receptor, and opioid regulates B.T. in maintenance stage via μ receptor.
During arousal from hibernation, the body temperature of hibernating hamster rapidly rises from 6 ℃ to 37 ℃. Thermogenesis in brown adipose tissue (BAT) is import component for the hyperthermia in the rodents including hamster. Thyrotropin-releasing hormone (TRH) produces the hyperthermia by increase of base metabolism. Therefore, we investigated the functional linkage of central TRH and BAT in the hyperthermia during arousal from hibernation. Intracerebroventricular (i.c.v.) administration of TRH produced hyperthermia in the hibernating hamster, and the hibernation was interrupted. In acute experiment, temperature of rectum and inter scapular BAT (iBAT) rose by the i.c.v. administration of TRH. The hyperthermic effect of TRH was suppressed by surgical denervation of iBAT and/or administration of SR59230 , a β3 adrenoceptor antagonist. I.c.v. administration of TRH caused increase of norepinephrine (NE) content and NE turnover rate in the iBAT. These results suggest that central TRH system and peripheral BAT system have functionally linked through the sympathetic nervous system, and it is play an important role in the hyperthermia during arousal from hibernation. Less
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