Effects of 5-HT1A receptor agonists on the circadian rhythm of wheel-running activity in hamsters.
The effects of 5-HT1A receptor agonists 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), buspirone and ipsapirone on wheel-running activity in hamsters were investigated in comparison with those of GABAA receptor agonist muscimol and benzodiazepine triazolam. Intraperitoneal administration of 8-OH-DPAT, buspirone, ipsapirone, muscimol and triazolam at circadian time (CT) 8 (CT 12; onset of activity) induced a significant phase advance of wheel-running activity under constant light conditions. However, administration of these drugs at other CT points did not induce phase changes. The administration of trifluoromethylphenylpiperazine (TFMPP), a 5-HT1B receptor agonist, at CT8 produced a small phase advance. The phase advance induced by 8-OH-DPAT was blocked by pretreatment with (-)-pindolol, a 5-HT1A receptor antagonist. In addition, 8-OH-DPAT, buspirone and SM3997 accelerated the rate of re-entrainment to an 8-h phase advance in the light-dark cycle. These observations suggest that 5-HT1A receptors in the brain participate in the regulation of the circadian rhythm of wheel-running activity in hamsters.
Tominaga
K
K
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
Shibata
S
S
Ueki
S
S
Watanabe
S
S
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000818:Animals; D002065:Buspirone / Q000494:pharmacology; D002940:Circadian Rhythm / Q000187:drug effects*; D006224:Cricetinae; D008297:Male; D008550:Melatonin / Q000494:pharmacology; D008647:Mesocricetus; D009043:Motor Activity / Q000187:drug effects*; D010869:Pindolol / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000032:analysis; D011985:Receptors, Serotonin / Q000032:analysis / Q000187:drug effects* / Q000502:physiology; D013764:Tetrahydronaphthalenes / Q000494:pharmacology
D010879:Piperazines; D011963:Receptors, GABA-A; D011985:Receptors, Serotonin; D013764:Tetrahydronaphthalenes; C018406:1-(3-trifluoromethylphenyl)piperazine; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D010869:Pindolol; D008550:Melatonin; D002065:Buspirone