Potentiation by Various Smooth Muscle Stimulants of an Isolated Sympathetic Nerve‐Seminal Vesicle Preparation from the Guinea‐Pig¹

The contractions of the seminal vesicle in response to hypogastric nerve stimulation or coaxial stimulation were recorded with a balloon inserted in the lumen of the seminal vesicle. Adrenaline (A), noradrenaline (NA), acetylcholine (Ach), histamine (Hi), serotonin (5‐HT), barium chloride and high concentrations of angiotensin were found to potentiate the motor response of the seminal vesicle to sympathetic nerve stimulation. This potentiation occurred with concentrations 10–100 times smaller than those giving a direct contraction of the organ. Prostaglandins (PGE 1 , PGE 2 and PGF 2 a ) in low concentrations (1–10 ng/ml) exerted no effect or caused a slight decrease in the response to sympathetic nerve stimulation, while higher concentrations (100 ng–1 μg/ml) enhanced the response to nerve stimulation. This effect was pronounced with PGE 1 , but rather weak with the other prostaglandins. Oxytocin, vasopressin and felypressin were without effect on the seminal vesicle preparation. It is concluded that the seminal vesicle responds to smooth muscle stimulants in a similar way as the vas deferens.