Nonspecific supersensitivity of the guinea-pig vas deferens produced by decentralization and reserpine treatment

Abstract

1. The sensitivity of the guinea-pig vas deferens to noradrenaline, histamine, methylfurmethide and potassium was examined in vitro following decentralization and reserpine treatment.2. One day after decentralization or administration of reserpine (1.0 mg/kg daily) the sensitivity of the vas deferens was not increased. After 5 days' treatment the muscle was supersensitive to all four stimulants.3. The magnitude of the sensitivity increase to an individual drug was the same following both chronic reserpine treatment and decentralization. However, the degree of supersensitivity differed for the four stimulants. The order of potentiation was noradrenaline>histamine>methylfurmethide>potassium.4. The magnitude of the supersensitivity was inversely correlated with the slope of the dose-response curves to the four agonists. The dose-response curve to potassium had the steepest slope, followed in order by methylfurmethide, histamine and noradrenaline.5. A hypothesis is presented to account for the inverse relationship between the slope of the dose-response curve and the degree of supersensitivity which follows reserpine treatment or decentralization.