Ethanol as a discriminative stimulus: effects of cyanamide, acetaldehyde and chlormethiazole.
Two groups of gerbils were trained to discriminate between either 2 g/kg of ethanol (ETOH) and saline or 2 g/kg of ETOH and 1 g/kg of ETOH. Acetaldehyde and a combination of cyanamide, an aldehyde dehydrogenase inhibitor, plus ETOH were tested to determine if augmented levels of acetaldehyde would enhance ETOH-like responses. The CNS depressant drug chlormethiazole (CMZ) was also tested, separately and in combination with ETOH. The effects of ETOH and acetaldehyde were also tested in an open-field (O--F). Some effect of acetaldehyde (ED50 = 160 mg/kg) was observed in the group trained to discriminate between saline and 2 g/kg of ETOH (ED50 = 800 mg/kg) but not in the group trained to discriminate between 1 and 2 g/kg ETOH. Cyanamide (50 mg/kg) given before 1 g/kg of ETOH did not markedly change the amount of ETOH (2 g/kg) appropriate responses as compared to the saline control. The percentage of ETOH (2 g/kg) appropriate choices increased after testing combinations of CMZ and ETOH as compared to testing either drug separately. ETOH stimulated ambulation (horizontal locomotor activity), whereas acetaldehyde resulted in a dose related decrease of all the behaviour patterns recorded in the O--F test. The major conclusions from these studies are that the behavioural pharmacology of acetaldehyde differs from that of ETOH, that acetaldehyde plays only a limited role in the discriminative stimulus effects of ethanol in gerbils, and that the stimulus effects of ETOH and CMZ are additive.
D000079:Acetaldehyde / Q000494:pharmacology*; D000818:Animals; D002719:Chlormethiazole / Q000494:pharmacology*; D003484:Cyanamide / Q000494:pharmacology*; D003486:Cyanides / Q000494:pharmacology*; D004193:Discrimination Learning / Q000187:drug effects*; D000431:Ethanol; D005260:Female; D005849:Gerbillinae; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects
D003486:Cyanides; D002719:Chlormethiazole; D000431:Ethanol; D003484:Cyanamide; D000079:Acetaldehyde