Effects of salsolinol, a tetrahydroisoquinolone alkaloid, on multiple schedule performance in rats

Rats were trained to lever press under a multiple fixed-ratio fixed-interval schedule of food reinforcement. Intracerebroventricular injections of salsolinol (1-methyl-6,7-dihydroxytetrahydroisoquinoline), a condensation product of dopamine and acetaldehyde, caused a dose-related decrease in fixed-ratio responding over a dosage range of 15-120 microgram. In contrast, fixed-interval responding was only reduced at the 120 microgram dose and was increased in two of the animals after injection of 15-30 microgram of salsolinol.