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Mechanisms of substance P‐induced pulmonary oedema in the rabbit: interactions between parasympathetic and excitatory NANC nerves
Author(s) -
Delaunois A.,
Gusti P.,
Ansay M.
Publication year - 1995
Publication title -
fundamental and clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 73
eISSN - 1472-8206
pISSN - 0767-3981
DOI - 10.1111/j.1472-8206.1995.tb00520.x
Subject(s) - hexamethonium , acetylcholine , substance p , atropine , tetrodotoxin , capsaicin , chemistry , muscarinic acetylcholine receptor , endocrinology , medicine , ruthenium red , cholinergic , excitatory postsynaptic potential , ganglionic blocker , pharmacology , inhibitory postsynaptic potential , biology , receptor , neuropeptide , calcium
Summary— The pharmacological mechanisms involved in the substance P (SP)‐induced pulmonary oedema were studied in isolated perfused rabbit lungs. Substance P induced a dose‐dependent increase in the capillary filtration coefficient (Kf,c), responsible for oedema. Atropine, hemicholinium‐3 and ruthenium red pretreatment partly protected the lungs against SP effects, while tetrodotoxin and hexamethonium did not significantly modify them. (±)CP96,345, a NK1 receptor antagonist, completely inhibited the SP‐induced increase in the Kf,c. Like SP, acetylcholine (ACh) and capsaicin also increased the Kf,c. Atropine and (±)CP96,345 completely blocked the oedema induced by both drugs. Tetrodotoxin and ruthenium red strongly inhibited the response to capsaicin and acetylcholine. It was concluded that SP‐induced pulmonary oedema is in part mediated by a stimulating action on cholinergic efferent nerves, with subsequent release of endogenous acetylcholine. Acetylcholine can, in turn, stimulate the release of SP from excitatory non adrenergic, non cholinergic nerves. The effects induced by capsaicin and exogenous acetylcholine, thus endogenous SP, involve tetrodotoxin‐sensitive mechanisms, while those produced by exogenous SP are tetrodotoxin‐resistant.