Prostate innervation.

The growth of the prostate gland has been considered to be controlled exclusively by endocrine means. The abundance of alpha adrenergic and muscarinic receptors and nerve fibers suggests that the autonomic nervous system may in fact play a role in the growth maturation and secretory functions of the prostate. The predominant adrenergic input to the prostate is from short adrenergic neurons, while cholinergic nerves are closely related to the glandular epithelium, presumably affecting a secretory function. The prostate has a high density of alpha-1 and beta-2 adrenergic receptors, and the presence of these receptors, as well as their regulation by androgens, suggests and supports the direct mitogenic effect of catecholamines on prostate growth. The activated signal transduction pathways in these neural systems also appear to modulate prostatic function and growth. Denervation of the prostate results in a loss of functional and structural integrity of the gland. The effects of sympathectomy and parasympathectomy support the conclusion that the dichotomy of function in prostatic autonomic innervation has a fundamental regulatory purpose. The majority of the afferent innervation to the ventral prostate is localized to sensory nerves from the L5 and L6 segments. There is some smaller degree of innervation from T13-L2. There is evidence of extensive bilateral innervation of pelvic viscera. Despite the importance of afferent sensory feedback in regulating the control of prostate growth, its effect is of a smaller magnitude than that observed with androgens. Regardless of the specific control mechanisms suggested by neural involvement in the growth differentiation and secretory function of the prostate, the presence of innervation appears to be consistent and reproducible, and holds great potential for increasing our understanding of pathologic influences in prostate disease.