DOPAMINERGIC INHIBITION OF 5-HYDROXYTRYPTAMINE-STIMULATED TESTICULAR MATURATION IN THE FIDDLER-CRAB, UCA PUGILATOR

The in vivo effects of dopamine (DA), a dopaminergic antagonist (spipe rone), and a dopaminergic agonist (ADTN) on maturation of the testes i n the fiddler crab, Uca pugilator, were determined, DA inhibited testi cular maturation dose-dependently. ADTN also inhibited maturation of t he testes whereas spiperone induced testicular maturation. These resul ts provide the first evidence for dopaminergic inhibition of testicula r maturation in a crustacean. This DA-induced inhibition may have been due to: (a) inhibition of release of the gonad-stimulating hormone, ( b) stimulation of release of the gonad-inhibiting hormone or (c) both (a) and (b).