Dissociation of amphetamine-induced release of norepinephrine from inhibition of neuronal uptake in isolated brain tissue

Abstract

Publisher Summary This chapter reviews the dissociation of amphetamine-induced release of norepinephrine (NE) from inhibition of neuronal uptake in isolated brain tissue. Neuronal uptake of 3H-norepinephrine into chopped rat brain tissue was measured by a method involving a 10 min incubation of chopped rat brain tissue with 10−7 M 3H-norepinephrine, and measuring total radioactivity in the incubation medium, and tissue. Drugs were added to the incubation medium 10 min before, and during the incubation with 3H-norepinephrine. Experimental samples were incubated at 37°C, and compared to control samples incubated at 0°C. It is found that because there is relatively little metabolism of 3H-norepinephrine in this 10 min exposure, 3H-norepinephrine was not separated from the deaminated metabolites. Results were expressed as tissue to medium ratios. This ratio approaches 1.0 at 0°C which indicates a lack of specific uptake at this temperature. The ratio was 7.1 ± 0.4 at 37°C in the absence of drugs, and this reflects approximately a sevenfold increase in uptake, and accumulation of 3H-norepinephrine into the tissue.