Tachykinin NK(2) receptors facilitate acetylcholine release from guinea-pig isolated trachea.
The release of newly synthesised [3H]acetylcholine was evoked by electrical field stimulation (5 Hz, 600 pulses) of epithelium-deprived guinea-pig trachea strips after sensory neuropeptides depletion with 3 microM capsaicin. The selective tachykinin NK(2) receptor agonist [betaAla(8)]neurokinin A-(4-10) increased in a concentration-dependent manner the electrically-induced release of [3H]acetylcholine. The facilitatory effect was antagonised by the selective non-peptide tachykinin NK(2) receptor antagonist, SR 48968 (apparent pK(B) 8.9). The tachykinin NK(1) and NK(3) receptor agonists substance P methyl ester and senktide (both 10 and 100 nM), respectively, did not affect the evoked release of [3H]acetylcholine. It is concluded that the cholinergic nerves of guinea-pig trachea are endowed with prejunctional facilitatory tachykinin receptors of the NK(2) subtype.
D'Agostino
G
G
University of Pavia, Institute of Pharmacology, Via Taramelli 14, I-27100, Pavia, Italy.
Erbelding
D
D
Kilbinger
H
H
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D002211:Capsaicin / Q000494:pharmacology; D002794:Choline / Q000378:metabolism; D004558:Electric Stimulation; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D015288:Neurokinin A / Q000031:analogs & derivatives / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D018041:Receptors, Neurokinin-2 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000187:drug effects*; D014132:Trachea / Q000187:drug effects / Q000378:metabolism*
D001549:Benzamides; D010446:Peptide Fragments; D010880:Piperidines; D018041:Receptors, Neurokinin-2; C064218:neurokinin A (4-10), beta-Ala(8)-; C073839:SR 48968; D015288:Neurokinin A; D002794:Choline; D000109:Acetylcholine; D002211:Capsaicin