TY - JOUR
T1 - Involvement of nitric oxide and vasoactive intestinal peptide in the nonadrenergic-noncholinergic relaxation of the porcine retractor penis muscle
AU - La, J.
AU - Kim, T.
AU - Sung, T.
AU - Kang, T.
AU - Lee, J.
AU - Yang, I.
PY - 2001
Y1 - 2001
N2 - Neurotransmitters mediating nonadrenergic-noncholinergic (NANC) relaxation were investigated in strips of porcine retractor penis muscle (RPM). Muscle tone was raised by phenylephrine (1 μM) in the presence of atropine (1 μM) and guanethidine (50 μM). Upon electrical field stimulation (1 ms, 80 V, 1 - 32 Hz for 10 s), the initial fast relaxation was followed by the slow relaxation. Although the fast and the slow relaxation were completely abolished by tetrodotoxin (1 μM), they showed different pharmacological sensitivities to the nitric oxide (NO) synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME, 0.1 mM). The fast relaxation was markedly inhibited by L-NAME in an L-arginine reversible manner and by oxyhemoglobin (50 μM), while the slow relaxation was hardly blocked by L-NAME. L-NAME and α-chymotrypsin (α-CT, 3 U/ml) selectively inhibited the fast and the slow relaxation, respectively. α-CT abolished L-NAME-resistant slow relaxation, and L-NAME completely abolished the α-CT-resistant fast relaxation. α-CT-resistant relaxation was not significantly different from the digitally calculated L-NAME-sensitive component, and L-NAME-resistant relaxation was similar to the digitally calculated α-CT-sensitive component. Vasoactive intestinal peptide (VIP, 0.003 - 0.1 μM) relaxed porcine RPM in a concentration-dependent manner. The effect of a VIP was partially inhibited by a VIP receptor antagonist, VIP(10 - 28) (1 and 3 μM). L-NAME-resistant relaxation was also reduced by VIP(10 - 28) (3 μM) and by another putative antagonist, VIP(6 - 28) (1 μM), although the effects of the two antagonists were somewhat inconsistent. From the histochemical staining, it was verified that nerve bundles that showed VIP-like immunoreactivities were also positive for the NADPH diaphorase reaction. These results suggest that NO and peptide neurotransmitter(s) including VIP mediate the NANC relaxation in porcine RPM.
AB - Neurotransmitters mediating nonadrenergic-noncholinergic (NANC) relaxation were investigated in strips of porcine retractor penis muscle (RPM). Muscle tone was raised by phenylephrine (1 μM) in the presence of atropine (1 μM) and guanethidine (50 μM). Upon electrical field stimulation (1 ms, 80 V, 1 - 32 Hz for 10 s), the initial fast relaxation was followed by the slow relaxation. Although the fast and the slow relaxation were completely abolished by tetrodotoxin (1 μM), they showed different pharmacological sensitivities to the nitric oxide (NO) synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME, 0.1 mM). The fast relaxation was markedly inhibited by L-NAME in an L-arginine reversible manner and by oxyhemoglobin (50 μM), while the slow relaxation was hardly blocked by L-NAME. L-NAME and α-chymotrypsin (α-CT, 3 U/ml) selectively inhibited the fast and the slow relaxation, respectively. α-CT abolished L-NAME-resistant slow relaxation, and L-NAME completely abolished the α-CT-resistant fast relaxation. α-CT-resistant relaxation was not significantly different from the digitally calculated L-NAME-sensitive component, and L-NAME-resistant relaxation was similar to the digitally calculated α-CT-sensitive component. Vasoactive intestinal peptide (VIP, 0.003 - 0.1 μM) relaxed porcine RPM in a concentration-dependent manner. The effect of a VIP was partially inhibited by a VIP receptor antagonist, VIP(10 - 28) (1 and 3 μM). L-NAME-resistant relaxation was also reduced by VIP(10 - 28) (3 μM) and by another putative antagonist, VIP(6 - 28) (1 μM), although the effects of the two antagonists were somewhat inconsistent. From the histochemical staining, it was verified that nerve bundles that showed VIP-like immunoreactivities were also positive for the NADPH diaphorase reaction. These results suggest that NO and peptide neurotransmitter(s) including VIP mediate the NANC relaxation in porcine RPM.
KW - Boar
KW - Nitric oxide
KW - Retractor penis muscle
KW - Vasoactive intestinal peptide
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U2 - 10.1254/jjp.86.236
DO - 10.1254/jjp.86.236
M3 - Article
C2 - 11459127
AN - SCOPUS:0034933484
SN - 0021-5198
VL - 86
SP - 236
EP - 243
JO - Japanese Journal of Pharmacology
JF - Japanese Journal of Pharmacology
IS - 2
ER -