On the use of the push-pull cannula as a means of measuring biochemical changes during ongoing behavior

Chronic indwelling push-pull cannulae (Gaddum, 1961) were implanted in the right lateral ventricles of two adult male and two adult female rats. Perfusion with artifical cerebrospinal fluid containing trace amounts of tritiated norepinephrine (H3-7-NE) was performed, under pentobarbital anesthesia, at rates of 20, 40, and 70 microl/min with two male rats and 40 and 70 microl/min with the female rats. Aliquots of perfusate were counted in order to determine if H3, from H3-7-NE varied as a function of perfusion rate, and volume loss, if any, was monitored by weighing tared collection vials. Perfusion of the male rats at 20 microl/min while they were working for food under fixed-ratio schedules of reinforcment indicated that this method might be used to study central biochemical-behavioral interactions using operant-conditioning procedures.