Further evidence for the mechanisms that may mediate nicotine discrimination.

Further evidence for the mechanisms that may mediate nicotine discrimination.

Schechter M D; Meehan S M

Pharmacology, biochemistry, and behavior

1992

1992-04

Rats were trained to discriminate the interoceptive stimuli produced by subcutaneously administered 0.4 mg/kg nicotine in a two-lever, food-motivated, operant task. Once criterion performance was attained, dose-response experiments indicated an ED50 value of 0.1 mg/kg and subsequent time course experiments showed a maximal effect between 10 and 30 min postadministration with a return to saline-like responding at 2 h. Pretreatment with the presynaptic dopamine release inhibitors CGS 10746B (30 mg/kg), as well as with the dihydropyridine calcium blocker isradipine (15 mg/kg), each produced a significant blockade of nicotine discrimination. In contrast, the 5-hydroxytryptamine (5-HT) receptor 5-HT3 antagonist ICS-205930 did not produce any effect upon nicotine discrimination. Thus, drugs that interfere with calcium influx, viz., isradipine, or with dopamine release (CGS 10746B) also interfere with nicotine discrimination and these results suggest that calcium influx and dopamine release may be necessary conditions for nicotine discrimination.

Animals; Calcium Channel Blockers/pharmacology; Dihydropyridines/pharmacology; Discrimination Learning; Dopamine/*metabolism; Dose-Response Relationship; Drug; Inbred Strains; Indoles/pharmacology; Isradipine; Male; Nicotine/administration & dosage/*pharmacology; Rats; Thiazepines/pharmacology; Tropisetron

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

807–812

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