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Titolo:
Skeletal muscle afferent fibres release substance P in the nucleus tractussolitarii of anaesthetized cats
Autore:
Potts, JT; Fuchs, IE; Li, JH; Leshnower, B; Mitchell, JH;
Indirizzi:
Univ235xas, SW Med Ctr, Harry S Moss Heart Ctr, Dept Physiol, Dallas, TX 75 Univ Texas Dallas TX USA 75235 oss Heart Ctr, Dept Physiol, Dallas, TX 75 UnivTXexas, SW Med Ctr, Harry S Moss Heart Ctr, Dept Internal Med, Dallas,Univ Texas Dallas TX USA 75235 Moss Heart Ctr, Dept Internal Med, Dallas,
Titolo Testata:
JOURNAL OF PHYSIOLOGY-LONDON
fascicolo: 3, volume: 514, anno: 1999,
pagine: 829 - 841
SICI:
0022-3751(19990201)514:3<829:SMAFRS>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
EXERCISE PRESSOR REFLEX; BARORECEPTOR REFLEX; CAROTID BAROREFLEX; DYNAMIC EXERCISE; BLOOD-PRESSURE; SPINAL-CORD; CARDIOVASCULAR CONTROL; INVIVO RELEASE; HEART-RATE; GROUP-III;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
54
Recensione:
Indirizzi per estratti:
Indirizzo: Potts, JT Univnesxas, SW Med Ctr, Harry S Moss Heart Ctr, Dept Physiol, 5323 Harry Hi Univ Texas 5323 Harry Hines Blvd Dallas TX USA 75235 23 Harry Hi
Citazione:
J.T. Potts et al., "Skeletal muscle afferent fibres release substance P in the nucleus tractussolitarii of anaesthetized cats", J PHYSL LON, 514(3), 1999, pp. 829-841

Abstract

1. The tachykinin substance P was recovered from the commissural subdivision of the nucleus tractus solitarii (cNTS) using in vivo microdialysis during activation of cardiorespiratory and skeletal muscle receptors in thirteen chloralose-anaesthetized cats.2. Tetanic muscle contraction was evoked by stimulating L7-S1 ventral roots (n=7). Electrically induced muscle contraction increased mean arterial pressure (MAP) by 55 +/- 10 mmHg and heart rate by 29 +/- g beats min(-1). During contraction the dialysate concentration increased 154% above resting control levels (from 0.217+/-0.009 to 0.546 +/- 0.023 fmol(100 mu l)(-1), control vs. contraction, P<0.05).3. Loss of cardiorespiratory input following disruption of the carotid sinus and vagus nerves significantly blunted, but did not abolish, the increase in substance P during muscle contraction (from 0.247,0.022 to 0.351 +/- 0.021 fmol(100 mu l)-1 control vs. contraction, P < 0.05). Approximately 44%of the substance P release during contraction was independent of cardiorespiratory input transmitted by carotid sinus and vagus nerves.4. To determine the contribution of cardiorespiratory related neural inputon substance P release, an intravascular balloon positioned in the thoracic aorta was inflated to increase arterial pressure (n = 6). Balloon inflation increased MAP by 50 +/- 5 mmHg and substance P increased from 0.251. +/-0.025 to 0.343 +/- 0.028 fmol (100 mu l)(-1) (control vs. balloon inflation, P< 0.05). This increase was completely abolished following interruption of vagal and carotid sinus nerves (from 0.301 +/- 0.002 to 0.311 +/- 0.004 fmol (100 mu l)(-1), control vs. balloon inflation). This finding shows that neural input from cardiorespiratory receptors (primarily arterial baroreceptors) accounted for 37% of the total substance P release during muscle contraction.5. The findings from this study demonstrate that activation of skeletal muscle receptors and cardiorespiratory receptors (predominantly arterial baroreceptors) increases the extraneuronal concentration of substance P in the cNTS. Because substance P release was not completely abolished during muscle contraction following disruption of carotid sinus and vagus nerves it is proposed that: (1) afferent projections from contraction-sensitive skeletalmuscle receptors may release substance P in the NTS; (2) neural input frommuscle receptors activates substance P-containing neurones within the NTS;and (3) convergence of afferent input from skeletal muscle receptors and arterial baroreceptors onto substance P-containing neurones in the cNTS facilitates the release of substance P. The role of tachykininergic modulation of cardiorespiratory input is discussed.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/11/20 alle ore 02:11:13