H. Matsuda et al., DIFFERENT MODES OF SENSORY NEUROPEPTIDES AND NITRIC-OXIDE INVOLVEMENTIN RELAXATION OF GUINEA-PIG VESSELS, Journal of the autonomic nervous system, 55(1-2), 1995, pp. 115-122
This study investigated involvement of calcitonin-gene-related peptide
(CGRP), substance P (SP) and nitric oxide (NO) in transmural nerve st
imulation (TNS)-induced non-adrenergic, non-cholinergic (NANC) relaxat
ion in isolated guinea pig anterior mesenteric artery (AMA) and poster
ior caval vein (PCV). Effects of cyclo-oxygenase-generated eicosanoids
were blocked with indomethacin (10(-5) M) and so were adrenergic and
cholinergic responses with phentolamine (3 X 10(-6) M), propranolol(10
(-6) M) and atropine (10(-6) M). In both vessels precontracted by U-46
619, TNS induced relaxation, which was almost completely abolished by
capsaicin pretreatment(10(-6) M, 15 minutes). In AMA, a CGRP(1) recept
or antagonist (human CGRP(8-37), 10(-5) M) significantly attenuated th
e relaxation, while did both human CGRP (8-37) (10(-5) M) and neurokin
in-1 receptor antagonists (spantide, 2X10(-5) M and FK888, 3X10(-6) M)
in PCV. N-G-nitro-L-arginine methyl ester (10(-4) M) did not signific
antly attenuate either the NANC-or CORP-induced relaxation in AMA. How
ever, it significantly did attenuate both the NANC-and SP-induced rela
xation, and it also considerably attenuated CORP-induced relaxation al
though insignificantly, in PCV. Thus, CORP could be significantly resp
onsible for the NO-independent NANC relaxation in AMA, whereas both CG
RP and SP could additionally relax PCV in a NO-dependent manner.