Pro-VGF-derived peptides induce penile erection in male rats

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Neuropharmacology. 2005 Dec;49(7):1017-25. Epub 2005 Aug 8.Click here

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Pro-VGF-derived peptides induce penile erection in male rats:

Involvement of paraventricular nitric oxide.

Succu S, Mascia MS, Melis T, Sanna F, Melis MR, Possenti R,

Argiolas A.

Bernard B. Brodie Department of Neuroscience and Center of

Excellence for the Neurobiology of Addiction, University of Cagliari,

S.P. Monserrato-Sestu, Km 0.700, 09042 Monserrato (CA), Italy.

The effect of four peptides derived from the C-terminal portion of

rat pro-VGF(556-617) (VGF(556-576), VGF(588-617), VGF(599-617), and

VGF(588-597)), on penile erection and nitric oxide production in the

paraventricular nucleus of the hypothalamus was studied in male rats

after injecting into this hypothalamic nucleus. VGF(588-617) (0.5, 1

and 2 microg), VGF(599-617) (0.5, 2 and 5 microg) and, to a lower

extent, VGF(588-597) (2 and 5 microg) induced penile erection episodes

when injected into the paraventricular nucleus and concomitantly

increased paraventricular nitric oxide production, while VGF(556-576)

(5 microg) was ineffective. VGF(588-617)-induced nitric oxide

production was reduced by N(G)-nitro-l-arginine methylester (l-NAME)

(20 microg), a nitric oxide synthase inhibitor, which also reduced

penile erection when injected in the paraventricular nucleus 15 min

before the VGF peptide. The oxytocin receptor antagonist

d(CH(2))(5)Tyr(Me)-Orn(8)-vasotocin (1 microg) also effectively

reduced VGF(588-617)-induced penile erection when given into the

lateral ventricles, but not when injected into the paraventricular

nucleus. In both experimental conditions,

d(CH(2))(5)Tyr(Me)-Orn(8)-vasotocin was unable to influence nitric

oxide production in the paraventricular nucleus. The present results

confirm that C-terminal pro-VGF-derived peptides induce penile

erection when injected into the paraventricular nucleus and show that

this effect is mediated by an increased nitric oxide production in

this hypothalamic nucleus. Apparently, this causes the activation of

paraventricular oxytocinergic neurons projecting to extra-hypothalamic

brain areas and mediating penile erection, as found with dopamine

agonists, oxytocin, excitatory amino acids and hexarelin analogue

peptides.

PMID: 16087201 [PubMed - indexed for MEDLINE]