Mechanical Responses of the Isolated Rabbit Testis to Electrical Stimulation and to Autonomic Drugs

Abstract

The Isolated testicular preparation of rabbit responded to acetylcholine, noradrenaline, adrenaline and isoproterenol with contractions or relaxations. Cholinergic and adrenergic receptor blocking agents revealed the presence of muscarinic receptors, and adrenergic α- and β-receptors in this preparation. Field stimulation with A. C. (3 V/cm, 50 Hz) or DMPP, elicited contractions which are susceptible to bretylium but to neither hexamethonium nor atropine. These results may rather be taken as evidence for the presence of adrenergic innervation to the rabbit testis. The testicular preparation showed slow spontaneous rhythmic contractions. These spontaneous contractions as well as the contractions elicited by field stimulation were entirely abolished by manganese ion. However, these contractions were resistant to TTX, and were little influenced even by removal of the parenchymal tissues from the capsule. These results may imply the possible presence of smooth muscle cells or other contractile tissues resembling smooth muscle cells within the testicular capsule.