THE UPTAKE AND RELEASE OF SEROTONIN AND DOPAMINE ASSOCIATED WITH LOCUST (LOCUSTA-MIGRATORIA) SALIVARY-GLANDS

The uptake and release characteristics of dopamine and serotonin in th e salivary glands of the locust Locusta migratoria were examined, Cycl ic AMP levels were determined in salivary glands in which the salivary nerve was stimulated under different experimental paradigms, Stimulat ion of the salivary nerve leads to time- and frequency-dependent eleva tions of cyclic AMP levels in the glands, The potent and specific D1 r eceptor antagonist SCH-23390 is capable of partially inhibiting the el ectrophysiologically induced elevations of cyclic AMP levels, The sali vary glands appear to possess uptake transporters for serotonin and do pamine, [H-3]serotonin uptake is Na+-dependent and is composed of high - and low-affinity components, [H-3]dopamine uptake is Na+-independent and can be partially reduced by a challenge with high-K+ saline and b y a challenge with ice-cold saline. Uptake inhibitors are capable of b locking the uptake of radiolabelled serotonin and dopamine, There is a Ca2+-dependent efflux of [H-3]serotonin and [H-3]dopamine from previo usly loaded salivary glands in response to stimulation of the salivary nerve and to treatment with a high-K+ saline.