Central Oxytocinergic Neurotransmission: A Drug Target for the Therapy of Psychogenic Erectile Dysfunction
A group of oxytocinergic neurons originating in the paraventricular nucleus of the hypothalamus and projecting to extrahypothalamic brain areas (e.g. hippocampus, medulla oblongata and spinal cord) control penile erection. Activation of these neurons by dopamine and dopamine agonists, excitatory amino acids (N-methyl-D-aspartic acid) or oxytocin itself, or by electrical stimulation leads to penile erection, while their inhibition by GABA and GABA agonists or by opioid peptides and opiate-like drugs inhibits this sexual response. The activation of oxytocinergic neurons in the paraventricular nucleus by dopamine, oxytocin and excitatory amino acids is apparently secondary to the activation of nitric oxide (NO) synthase. NO in turn activates, by a mechanism that is as yet unidentified, the release of oxytocin from oxytocinergic neurons in extrahypothalamic brain areas. Several peptide analogues of hexarelin, a growth hormone releasing peptide, also induce penile erection when injected into the paraventricular nucleus and, to a lesser extent, systemically, apparently by acting on a specific receptor to activate oxytocinergic neurons as shown for the above drugs and oxytocin. Paraventricular oxytocinergic neurons and mechanisms similar to those reported above are also involved in the expression of penile erection in physiological contexts, namely when penile erection is induced in the male by the presence of an inaccessible receptive female, which is considered a model for psychogenic impotence in man, as well as during copulation. These findings show that paraventricular oxytocinergic neurons projecting to extra-hypothalamic brain areas and to the spinal cord are a likely target for the treatment of erectile dysfunction of central origin.
No Supplementary Data
No Article Media
Document Type: Review Article
Publication date: 01 January 2003
More about this publication?
- Current Drug Targets aims to cover the latest and most outstanding developments on the medicinal chemistry and pharmacology of molecular drug targets e.g. disease specific proteins, receptors, enzymes, genes. Each issue of the journal will be devoted to a single timely topic, with series of in-depth reviews, written by leaders in the field, covering a range of current topics on drug targets. These issues will be organized and led by a guest editor who is a recognized expert in the overall topic. As the discovery, identification, characterisation and validation of novel human drug targets for drug discovery continues to grow; this journal will be essential reading for all pharmaceutical scientists involved in drug discovery and development.