title: Atropine in the abstinence after chronic barbital treatment in the rat.
abstract: Since cholinergic mechanisms seem to be involved in the changes induced by chronic barbital treatments in male rats, various treatments with atropine were given during the abstinence after 32--33 weeks of exposure to barbital (200 mg/kg/day). The effects of the atropine treatment were recorded as a tolerance towards a hexobarbital anaesthesia threshold. In Experiment 1, 1.5 mg/kg/day of atropine was given on Days 23--29 after the end of the barbital treatment. Two weeks after the end of the atropine treatment a significant tolerance (+ 16%, Fig. 1A) was seen in barbital-treated animals given the atropine treatment (group BA), but not in the corresponding control groups (group BS, CA and CS). In Experiment 2, the atropine dose was 4 mg/kg/day and the treatment was given on Days 29--44. A tolerance (+ 20%, Fig. 4) with maximum 2 weeks after the end of the atropine treatment was recorded in the animals given the combined treatment (group BA). In both experiments a single dose of atropine given on Day 3 reduced this tolerance. In Experiment 3 the atropine treatment was 4 mg/kg/day on Days 3--12. A tolerance above that induced by the barbital treatment (+ 16%, Fig. 5) was recorded three weeks after the end of the atropine treatment (group BA). In this group there was also recorded a new tolerance much later (Day 80). Since a tolerance was induced by atropine, only in previously barbital-treated animals, a carry-over of some change in cholinergic mechanisms is probably involved.
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology*; D001462:Barbital / Q000494:pharmacology*; D001463:Barbiturates / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004361:Drug Tolerance; D006591:Hexobarbital / Q000494:pharmacology; D006801:Humans; D008297:Male; D051381:Rats; D011950:Receptors, Cholinergic / Q000187:drug effects; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology*; D013997:Time Factors
chemical_list: D001463:Barbiturates; D011950:Receptors, Cholinergic; D001462:Barbital; D001285:Atropine; D006591:Hexobarbital