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Titolo:
Characterization of vagal input to the rat esophageal muscle
Autore:
Storr, M; Geisler, F; Neuhuber, WL; Schusdziarra, V; Allescher, HD;
Indirizzi:
Tech Univ Munich, GAP, Dept Internal Med 2, D-81675 Munich, Germany Tech Univ Munich Munich Germany D-81675 l Med 2, D-81675 Munich, Germany Univ Erlangen Nurnberg, Dept Anat, D-91054 Erlangen, Germany Univ ErlangenNurnberg Erlangen Germany D-91054 -91054 Erlangen, Germany
Titolo Testata:
AUTONOMIC NEUROSCIENCE-BASIC & CLINICAL
fascicolo: 1-2, volume: 91, anno: 2001,
pagine: 1 - 9
SICI:
1566-0702(20010813)91:1-2<1:COVITT>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOTOR END-PLATES; NICOTINIC ACETYLCHOLINE-RECEPTORS; CONTAINING NERVE-TERMINALS; GUINEA-PIG ESOPHAGUS; NITRIC-OXIDE; MUSCULARIS MUCOSAE; STRIATED-MUSCLE; ENTERIC NEURONS; SMOOTH-MUSCLE; INNERVATION;
Keywords:
N. vagus; esophageal muscle; NO; autonomic nervous system;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
28
Recensione:
Indirizzi per estratti:
Indirizzo: Storr, M Tech Univ Munich, GAP, Dept Internal Med 2, Ismaningerstr 22, D-81675 Munich, Germany Tech Univ Munich Ismaningerstr 22 Munich Germany D-81675 Germany
Citazione:
M. Storr et al., "Characterization of vagal input to the rat esophageal muscle", AUTON NEURO, 91(1-2), 2001, pp. 1-9

Abstract

There is recent morphological evidence for an interaction of autonomic nerve fibers and extrinsic motor nerves of the rat esophagus. The aim of the present study was to investigate a possible functional role of this autonomic innervation of vagal motor fibers on rat esophageal smooth and striated muscle function in vitro. The entire esophagus with both Nn vagi, including the Nn recurrentes, was dissected and placed in an organ bath with oxygenated Krebs-Ringer buffer. Contractile activity was measured in longitudinal direction with a force transducer. Both Nn vagi were placed on a bipolar platinum electrode 2 cm apart from the esophagus. Vagal stimulation, applied for 1 s (40 V, 0.5 ms, 20 Hz) resulted in a biphasic contractile response, which was completely blocked by tetrodotoxin (10(-6) M). The first part consisted of a tetanic striated muscle contraction, which was abolished by tubocurarin (10(-5) M) but unaffected by atropine (10-6 M) or hexamethonium (10(-4) M). In contrast, the second part was completely abolished by hexamethonium (10-4 M) and atropine 10(-6) M), whereas tubocurarine (10(-5) M) showed no influence, suggesting a stimulation of preganglionic nerve fibers supplying esophageal smooth muscle (muscularis mucosae). In order to characterize possible autonomic transmitters of the ENS of the esophagus, the following experiments were carried out. The magnitude of the striated muscle response was unaffected by VIP (10(-7) M), 5-HT (10(-6) M) and galanin (10(-8)-10(-7) M), whereas they caused an inhibition of the smooth muscle response (VIP: -53.8 +/- 4.2%; galanin 10(-8) M: - 18.5 +/- 2.2%; 10(-7) M: -40.4 +/-2.9%; 5-HT: -78.2 +/- 2.1%). The inhibitory effects of VIP and galanin on smooth muscle were reversible by the antagonists VIP 10-28 and galanin 1-15. In the presence of the nitric oxide synthase (NOS) inhibitor L-NNA (10(-4) M), the smooth and striated muscle contraction were not significantly influenced. Exogenous application of the NO-donor DEA-NO (10(-4) M) reduced the smooth muscle contraction by - 81.6 +/- 7.4%, but had no significant effect on the striated muscle contraction. Though immunohistochemical findings are highly suggestive of an nitrergic autonomic modulation of striated muscle contraction by enteric neurons, we could not demonstrate a NO-mediated action on striated muscle activity. Therefore, the physiological relevance of the immunohistochemical findings remain unclear. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/12/20 alle ore 01:03:54