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Evidence for the involvement of both ATP and nitric oxide in non‐adrenergic, non‐cholinergic inhibitory neurotransmission in the rabbit portal vein
Author(s) -
Brizzolara Antonia L.,
Crowe Rahima,
Burnstock Geoffrey
Publication year - 1993
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1993.tb13614.x
Subject(s) - suramin , sodium nitroprusside , inhibitory postsynaptic potential , neurotransmission , nitroarginine , cholinergic , nitric oxide synthase , endocrinology , medicine , adrenergic , nitric oxide , acetylcholine , tetrodotoxin , chemistry , biology , receptor
The NANC inhibitory innervation of the longitudinal muscle of the rabbit portal vein has been examined. Neurogenic relaxations were partially inhibited by the P 2 ‐purinoceptor antagonist, suramin. Addition of the NO‐synthase inhibitor N G ‐nitro‐ l ‐arginine methyl ester ( l ‐NAME) also significantly reduced responses to electrical stimulation and the addition of l ‐arginine reversed this effect. A combination of both suramin and l ‐NAME abolished the neurogenic relaxation. A maximum relaxation of the vein was evoked by sodium nitroprusside which was not affected by l ‐NAME or suramin. Histochemical staining demonstrated the presence of NADPH‐diaphorase containing nerves between the longitudinal and circular muscle coats of the media and also in the adventitia. It is concluded that both ATP and NO are inhibitory neurotransmitters in the NANC nerves of the rabbit portal vein.