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Titolo:
EFFECTS OF NOISE STRESS ON EFS-MEDIATED CHOLINERGIC AND INHIBITORY NANC RESPONSES IN TRACHEAS FROM NORMAL AND SENSITIZED GUINEA-PIGS
Autore:
BRESCHI MC; NIERI P; LAZZERI N; MARTINOTTI E;
Indirizzi:
UNIV PISA,FAC PHARM,INST BIOL SCI,VIA BONANNO 6 I-56126 PISA ITALY
Titolo Testata:
Journal of autonomic pharmacology
fascicolo: 6, volume: 17, anno: 1997,
pagine: 353 - 363
SICI:
0144-1795(1997)17:6<353:EONSOE>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
NITRIC-OXIDE SYNTHASE; SMOOTH-MUSCLE; HUMAN AIRWAYS; RECEPTOR SUBTYPES; NERVE-STIMULATION; ADENOSINE; LUNG; RELAXATION; SYSTEM; HISTAMINE;
Tipo documento:
Article
Natura:
Periodico
Citazioni:
50
Recensione:
Indirizzi per estratti:
Citazione:
M.C. Breschi et al., "EFFECTS OF NOISE STRESS ON EFS-MEDIATED CHOLINERGIC AND INHIBITORY NANC RESPONSES IN TRACHEAS FROM NORMAL AND SENSITIZED GUINEA-PIGS", Journal of autonomic pharmacology, 17(6), 1997, pp. 353-363

Abstract

1 The aim of the present research was to study the cholinergic and inhibitory non-adrenergic-noncholinergic (NANC) responses obtained with electrical field stimulation (EFS) of tracheal tissues from sham-and noise-exposed guinea-pigs. A comparison was also made between normal and ovalbumin (OA)-sensitized animals. 2 In proximal tracheae pretreatedwith indomethacin (3 mu M), propranolol (1 mu M), alpha-chymotrypsin (2 U ml(-1)) and L-NAME (0.1 mM), frequency-dependent responses to EFS(0.1 ms width; 20 V, 0.1-100 Hz, 15 s train duration) were obtained, both contractile and relaxing in nature. The contractile responses were abolished by atropine (1 mu M), and did not vary significantly between sham-and noise-exposed guinea-pigs, or between normal and sensitized animals. The NANC relaxing responses, present in spite of the pre-treatment of the tissues with L-NAME and alpha-chymotrypsin, and almost completely abolished by tetrodotoxin (TTX) treatment (10 mu M), appeared to be enhanced in noise-exposed guinea-pigs, with respect to sham-exposed animals, but only when the animals were not OA-sensitized. 3 Indistal tracheae contracted with histamine (10 mu M), the study of thewhole inhibitory NANC response (pre-treatment with propranolol, but not with alpha-chymotrypsin and L-NAME), which was mainly TTX-sensitive, revealed a statistically non-significant difference between sham-andnoise-exposed guinea-pigs, both normal and OA-sensitized. When distaltracheae were preincubated with alpha-chymotrypsin (2 U ml(-1)) and L-NAME (0.1 mM), in addition to propranolol, a significant residual inhibitory NANC response to EFS was observed. Surprisingly, in this case,similarly to the evidence obtained in proximal tracheae, a significantly enhanced response was revealed in noise-exposed guinea-pigs with respect to sham-exposed animals. 4 The noise-induced enhancement of therelaxant response disappeared when the tissues were pretreated with the A(2) purinergic antagonist 3,7-dimethyl-1-propargylxanthine (DMPX, 1 mu M), while it persisted in the presence of the A(1) antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX, 10 nM). 5 The above data indicate that, while not modifying the cholinergic and the whole inhibitoryNANC response to EFS, noise stress selectively influences an inhibitory component of the NANC system in guinea-pig trachea with a mechanismprobably involving an enhanced neurally mediated release of adenosine, which relaxes the smooth muscle via A(2) receptors. This effect appears to be lacking or masked in sensitized guinea-pigs.

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Documento generato il 24/09/20 alle ore 00:50:02