Species differences in the actions of sensory neuropeptides on contractility of the smooth muscle of the rat and guinea-pig prostate

1. The present review describes the actions of sensory neuropeptides on the contractility of the rat and guinea-pig prostate gland and discusses the d ifferences in sensitivity of the smooth muscle of the prostates taken from these species to these neuropeptides. 2. Nerve fibres immunoreactive for the tachykinins substance P and neurokin in A, as well as for the sensory neuropeptide calcitonin gene-related pepti de (CGRP), are sparsely distributed throughout the fibromuscular stroma of the prostate gland in both the rat and guinea-pig. 3. In functional experiments, tachykinin agonists potentiate electrical fie ld stimulation-induced contractile responses of prostates taken from guinea -pigs, but have no effect on those taken from rats. This potentiation is th rough stimulation of tachykinin NK1-receptors. 4. Conversely, CGRP inhibits electrical field stimulation-induced contracti le responses of prostates taken from rats, but has no effect on those taken from guinea-pigs. 5. It is concluded that although the sensory innervation to the prostate gl ands of the rat and guinea-pig appears similar, the nature and sensitivity of the contractile response of the prostatic smooth muscle to applied senso ry neuropeptides is vastly different in the two species.