Central control of penile erection: role of the paraventricular nucleus of the h

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Prog Neurobiol. 2005 May;76(1):1-21.Click here to read Links

Central control of penile erection: role of the paraventricular

nucleus of the hypothalamus.

Argiolas A, Melis MR.

Bernard B. Brodie Department of Neuroscience, Centre of Excellence

for the Neurobiology of Addictions, University of Cagliari, S.P.

Sestu-Monserrato Km 0.700, 09042 Monserrato, Cagliari, Italy.

argiolas@...

The paraventricular nucleus of the hypothalamus is an integration

centre between the central and peripheral autonomic nervous systems.

It is involved in numerous functions from feeding, metabolic balance,

blood pressure and heart rate, to erectile function and sexual

behaviour. In particular, a group of oxytocinergic neurons originating

in this nucleus and projecting to extra-hypothalamic brain areas

(e.g., hippocampus, medulla oblongata and spinal cord) control penile

erection in male rats. Activation of these neurons by dopamine and its

agonists, excitatory amino acids (N-methyl-D-aspartic acid) or

oxytocin itself, or by electrical stimulation leads to penile

erection, while their inhibition by gamma-amino-butyric acid (GABA)

and its agonists or by opioid peptides and opiate-like drugs inhibits

this sexual response. The activation of these neurons is secondary to

the activation of nitric oxide synthase, which produces nitric oxide.

Nitric oxide in turn causes, by a mechanism that is as yet

unidentified, the release of oxytocin in extra-hypothalamic brain

areas. Other compounds recently identified that facilitate penile

erection by activating central oxytocinergic neurons are peptide

analogues of hexarelin, a growth hormone releasing peptide,

pro-VGF-derived peptides, endogenous peptides that may be released by

neuronal nerve endings impinging on oxytocinergic cell bodies, SR

141716A, a cannabinoid CB1 receptor antagonist, and, less

convincingly, adrenocorticotropin-melanocyte-stimulating hormone

(ACTH-MSH)-related peptides. Paraventricular oxytocinergic neurons and

similar mechanisms are also involved in penile erection occurring in

physiological contexts, namely noncontact erections that occur in male

rats in the presence of an inaccessible receptive female, and during

copulation. These findings show that the paraventricular nucleus of

the hypothalamus plays an important role in the control of erectile

function and sexual activity. As the male rat is a model of sexual

behaviour and penile physiology, which has largely increased in the

last years our knowledge of peripheral and central mechanisms

controlling erectile function (drugs that induce penile erection in

male rats usually do so also in man), the above results may have great

significance in terms of a human perspective for the treatment of

erectile dysfunction.

PMID: 16043278 [PubMed - indexed for MEDLINE]