Activation of melanocortin MC4 receptors increases erectile activity in rats ex copula

Martin, William J.; McGowan, Erin; Cashen, Doreen E.; Gantert, Liza; Drisko, Jennifer E.; Hom, Gary J.; Nargund, Ravi P.; Sebhat, Iyassu K.; Howard, Andrew D.; Ploeg, Lex H.T. Van der; MacIntyre, D. Euan

doi:10.1016/s0014-2999(02)02479-2

Cited by 79 publications

(60 citation statements)

References 26 publications

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“…26 So, the APO test may be accepted as a measure and the parameters used to interpret the erectile function in conscious rats. [27][28][29][30] The mean blood pressure was significantly higher in group A than in group B and there were no significant serum testosterone levels between the two groups. Accordingly, the erectile frequency was significantly reduced in group A compared with group B (0.4070.55 vs 2.4071.14) after the two groups of Ultrastructural comparison of penile cavernous tissue in SHR and normotensive rat R Jiang et al rats were treated with APO injection.…”

Section: Discussionmentioning

confidence: 80%

Ultrastructural comparison of penile cavernous tissue between hypertensive and normotensive rats

et al. 2005

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Our aim was to compare the ultrastructure of penile cavernous tissue in the spontaneous hypertensive rat (SHR) and normotensive rat, and study the relation of blood pressure with erectile function. After injection of apomorphine (APO), penile erectile frequency in 16-week-old SHR (group A) and Wistar-Kyoto rat (WKY) (group B) was observed and noted. The ultrastructure of the penile cavernous tissue was studied by scanning electron microscope and transmission electron microscope. The mean blood pressures were significantly higher in group A than in group B (P ¼ 0; 171.20710.94 and 117.60712.38, n ¼ 5, for group A and group B, respectively). After treatment of the two groups with APO, the erectile frequency in group A was significantly less than in group B (P ¼ 0.007; 0.4070.55 and 2.4071.14, n ¼ 5, for group A and group B, respectively). Significant ultrastructural pathological changes were observed in the tunica albuginea and penile cavernous tissue of SHR. The elastic fibers were decreased and the collagen fibers of the sinusoid were increased in group A. The tunica albuginea thickness (mean7s.d.) was 100.2077.22 lm and 126.0077.65 lm in group A and group B, respectively. The tunica albuginea of group A was significantly thinner than that in B (P ¼ 0.001). Some endothelial cells and smooth muscle cells exhibited damaged mitochondria, and endoplasmic reticulums and Schwann cells were degenerated in group A. Although the function of penile erection might be affected by a secondary effect related to endothelial dysfunction of hypertension, these ultrastructural pathological changes of the penile cavernous tissue might also be one of the important mechanisms of erectile dysfunction caused by hypertension.

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Section: Discussionmentioning

confidence: 80%

Ultrastructural comparison of penile cavernous tissue between hypertensive and normotensive rats

et al. 2005

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“…However, the finding that erections induced by α-MSH [23] and ACTH [24] were not interrupted by oxytocin antagonism has not been confirmed by later experiments [25]. Some interaction of the systems seems probable in view of the shared anatomic sites in the brain and endpoint in terms of erectile function.…”

Section: Other Pathwaysmentioning

confidence: 92%

Melanocortins in sexual function

Heaton

Morales

Adams

2004

Curr sex health rep

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“…In further support that α-MSH act through different central mechanisms than those of dopamine and oxytocin to regulate penile erection, an oxytocin receptor antagonist failed to attenuate erections in response to α-MSH after intracerebroventricular administration to rats [33]. In contrast, another oxytocin receptor antagonist was shown to counteract erectile activity induced by systemic or central administration of a selective MC4 receptor agonist [34].…”

Section: Melanocortins and Mc-receptorsmentioning

confidence: 92%

“…An antagonist for the MC3 and MC4 receptors effectively counteracted MT-II-induced erections, whereas an antagonist for the MC4 receptor only partially counteracted α-MSH-induced erections [42,43]. A highly selective MC4 receptor agonist, THIQ, was shown to increase the numbers of erections in a rat model after intravenous or intracerebroventricular administration, and these effects were blocked by an MC4-preferring antagonist [34]. Although PT-141 is reported to have some selectivity preference for the MC4 subtype receptor [6], no information is available regarding the effects of agonists with high selectivity for the MC4 subtype on erectile function in humans.…”

Section: Melanocortins and Mc-receptorsmentioning

confidence: 96%