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Leptin enhances nitric oxide-dependent relaxation of the clitoral corpus cavernosum.

Lee SY, Chung WH, Lee MY, Kim SC, Kim HW, Myung SC - Korean J Urol (2011)

Bottom Line: L-NAME pretreatment significantly reduced the effect of leptin on ACh-induced relaxation, whereas L-arginine potentiated the effect of leptin.Leptin decreased the KCl-induced contractile responses.These relaxation effects of leptin may occur through an NO-dependent mechanism and voltage-dependent calcium channel blockade.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Seoul Medical Center, Seoul, Korea.

ABSTRACT

Purpose: The effects of leptin on female sexual behaviors are controversial, and studies on this topic are limited. The objectives of this study were to evaluate the direct effects of leptin on clitoral vasoreactivity in vitro and to determine the mechanism of action.

Materials and methods: Isometric tension studies were conducted to determine the effects of pretreatment with leptin (10(-8) M) on the contractile responses of rabbit clitoral corpus cavernosal smooth muscle strips. The effects of leptin were assessed on precontraction induced by phenylephrine (PE; 10(-9)-10(-4) M) and KCl (35-140 mM). We also examined the effect of leptin on relaxation induced by acetylcholine (ACh; 10(-9)-10(-4) M), verapamil (10(-10)-10(-6) M), and sodium nitroprusside (10(-9)-10(-4) M) in PE-precontracted (10(-5) M) strips.

Results: Leptin enhanced ACh-induced relaxation in PE-precontracted strips. L-NAME pretreatment significantly reduced the effect of leptin on ACh-induced relaxation, whereas L-arginine potentiated the effect of leptin. Leptin decreased the KCl-induced contractile responses. Leptin increased verapamil-induced relaxation responses. The relaxation effects of leptin on KCl-induced contraction were inhibited by 10(-5) M methylene blue and L-NAME pretreatment.

Conclusions: A high concentration of leptin enhances ACh-dependent relaxation in clitoral cavernosal smooth muscles. These relaxation effects of leptin may occur through an NO-dependent mechanism and voltage-dependent calcium channel blockade.

No MeSH data available.


Related in: MedlinePlus

Concentration-response curves for the effect of leptin pretreatment on contraction in rabbit clitoral corpus cavernosal strips in a phenylephrine dose-dependent manner (n=8).
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Figure 1: Concentration-response curves for the effect of leptin pretreatment on contraction in rabbit clitoral corpus cavernosal strips in a phenylephrine dose-dependent manner (n=8).

Mentions: The strips were pretreated with 10-8 M leptin and then administered PE (10-9-10-4 M) in the organ bath. No change in contractile responses was observed (n=8) (Fig. 1). The strips were pretreated with 10-8 M leptin and then ACh (10-9-10-4 M) was administered to PE-induced precontracted strips. Leptin significantly enhanced the ACh-induced endothelium-dependent relaxation (n=12) (Fig. 2).


Leptin enhances nitric oxide-dependent relaxation of the clitoral corpus cavernosum.

Lee SY, Chung WH, Lee MY, Kim SC, Kim HW, Myung SC - Korean J Urol (2011)

Concentration-response curves for the effect of leptin pretreatment on contraction in rabbit clitoral corpus cavernosal strips in a phenylephrine dose-dependent manner (n=8).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3045720&req=5

Figure 1: Concentration-response curves for the effect of leptin pretreatment on contraction in rabbit clitoral corpus cavernosal strips in a phenylephrine dose-dependent manner (n=8).
Mentions: The strips were pretreated with 10-8 M leptin and then administered PE (10-9-10-4 M) in the organ bath. No change in contractile responses was observed (n=8) (Fig. 1). The strips were pretreated with 10-8 M leptin and then ACh (10-9-10-4 M) was administered to PE-induced precontracted strips. Leptin significantly enhanced the ACh-induced endothelium-dependent relaxation (n=12) (Fig. 2).

Bottom Line: L-NAME pretreatment significantly reduced the effect of leptin on ACh-induced relaxation, whereas L-arginine potentiated the effect of leptin.Leptin decreased the KCl-induced contractile responses.These relaxation effects of leptin may occur through an NO-dependent mechanism and voltage-dependent calcium channel blockade.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Seoul Medical Center, Seoul, Korea.

ABSTRACT

Purpose: The effects of leptin on female sexual behaviors are controversial, and studies on this topic are limited. The objectives of this study were to evaluate the direct effects of leptin on clitoral vasoreactivity in vitro and to determine the mechanism of action.

Materials and methods: Isometric tension studies were conducted to determine the effects of pretreatment with leptin (10(-8) M) on the contractile responses of rabbit clitoral corpus cavernosal smooth muscle strips. The effects of leptin were assessed on precontraction induced by phenylephrine (PE; 10(-9)-10(-4) M) and KCl (35-140 mM). We also examined the effect of leptin on relaxation induced by acetylcholine (ACh; 10(-9)-10(-4) M), verapamil (10(-10)-10(-6) M), and sodium nitroprusside (10(-9)-10(-4) M) in PE-precontracted (10(-5) M) strips.

Results: Leptin enhanced ACh-induced relaxation in PE-precontracted strips. L-NAME pretreatment significantly reduced the effect of leptin on ACh-induced relaxation, whereas L-arginine potentiated the effect of leptin. Leptin decreased the KCl-induced contractile responses. Leptin increased verapamil-induced relaxation responses. The relaxation effects of leptin on KCl-induced contraction were inhibited by 10(-5) M methylene blue and L-NAME pretreatment.

Conclusions: A high concentration of leptin enhances ACh-dependent relaxation in clitoral cavernosal smooth muscles. These relaxation effects of leptin may occur through an NO-dependent mechanism and voltage-dependent calcium channel blockade.

No MeSH data available.


Related in: MedlinePlus