Central noradrenergic control of penile erection

Penile erection is completely dependent on commands from the central nervou s system. Spinal centers controlling penile erection are located in the tho racolumbar and lumbosacral spinal cord. These centers are activated by info rmation from the periphery and supraspinal nuclei so as to elicit penile er ection in a variety of physiological contexts. A small number of nuclei inc luding the locus coeruleus located in the pens sends noradrenergic fibers t o the forebrain and spinal cord, including those areas controlling penile e rection. Recent morphological techniques such as in situ hybridization and autoradiography using radioligand binding permit investigation of the brain and spinal pathways utilizing alpha adrenoceptor subtypes. Furthermore, ph armacological experiments suggest a modulatory role for noradrenaline in th e control of penile erection either in the brain or in the spinal cord. The most robust evidence is that central inhibition of alpha-2 adrenoceptors f acilitates sexual function. Taken together, the data propose new directions in the physiological exploration of penile erection and the therapeutic ap proach of erectile dysfunction.