Table 1.

Summary of findings of pre-clinical studies reviewed.

receptor subtype	antagonist/agonist	effect	behaviour	reference
α	agonist	↓	acquisition of nicotine self-administration	67
α	agonist	↓	maintenance of nicotine self-administration FR schedule	67, 68
α	agonist	-	responding for food FR schedule	25, 67, 68
α	agonist	-	drug discrimination	68
α	agonist	↓	ethanol intake	69
α	agonist	↑	ethanol intake	70
α	agonist	↓	nicotine-induced reinstatement	67, 68
α	agonist	↓	cue-induced reinstatement of nicotine-seeking	67
α	agonist	-	sensitization to cocaine	71
α	agonist	↑	sensitization to morphine	71
γ	agonist	↓	intake of alcohol	73
γ	agonist	↑	food intake	73
γ	agonist	-	water intake	73
γ	agonist	↓	self-administration of ethanol	73
γ	agonist	↓	self-administration of heroin FR schedule	75
γ	agonist	↓	self-administration of heroin PR schedule	75
γ	agonist	-	cue-induced reinstatement of alcohol-seeking	73
γ	agonist	↓	yohimbine-induced reinstatement of alcohol-seeking	73
γ	agonist	↓	Methamphetamine sensitization	78
γ	antagonist	↑	Methamphetamine sensitization	78