Different effects of L-type and T-type calcium channel blockers on the hypnotic potency of triazolam and zolpidem in rats.
We examined the effects of an L-type Ca2+ channel blocker, nilvadipine (0.5 and 2.0 mg/kg), and that of a T-type Ca2+ channel blocker, flunarizine (10.0 and 40.0 mg/kg), on the hypnotic potency of both a benzodiazepine (BZ)-hypnotic, triazolam (1.0 mg/kg), and a non-BZ hypnotic, zolpidem (20.0 mg/kg), in rats. The polysomnogram was recorded for 6 h after administration of the vehicle solution alone, or after one of the Ca2+ channel blockers, with or without one of the hypnotics. Both Ca2+ channel blockers prolonged the increased total time of non-rapid eye movement (non-REM) sleep induced by either hypnotic. In the case of triazolam, however, the non-REM sleep-enhancing effect induced by nilvadipine was greater than that induced by flunarizine. These findings indicate that the hypnotic action of triazolam is potentiated more strongly by an L-type Ca2+ channel blocker than by a T-type Ca2+ channel blocker.
Takahashi
H
H
Department of Neuropsychiatry, Akita University School of Medicine, Akita-City, Japan.
Yoshimoto
M
M
Higuchi
H
H
Shimizu
T
T
Hishikawa
Y
Y
D000818:Animals; D002121:Calcium Channel Blockers / Q000145:classification / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects* / Q000378:metabolism; D020746:Calcium Channels, L-Type; D020747:Calcium Channels, T-Type; D004347:Drug Interactions; D005444:Flunarizine / Q000494:pharmacology; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D009543:Nifedipine / Q000031:analogs & derivatives / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012895:Sleep, REM / Q000187:drug effects; D014229:Triazolam / Q000494:pharmacology*; D000077334:Zolpidem
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D020747:Calcium Channels, T-Type; D006993:Hypnotics and Sedatives; D011725:Pyridines; C035100:nilvadipine; D014229:Triazolam; D000077334:Zolpidem; D009543:Nifedipine; D005444:Flunarizine