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Titolo:
Reflex cardiovascular responses evoked by selective activation of skeletalmuscle ergoreceptors
Autore:
Leshnower, BG; Potts, JT; Garry, MG; Mitchell, JH;
Indirizzi:
Univ Texas, SW Med Ctr, Dept Internal Med, Dallas, TX 75390 USA Univ Texas Dallas TX USA 75390 r, Dept Internal Med, Dallas, TX 75390 USA Univ Texas, SW Med Ctr, Harry S Moss Heart Ctr, Dept Anesthesiol & Pain Management, Dallas, TX 75390 USA Univ Texas Dallas TX USA 75390 ol & Pain Management, Dallas, TX 75390 USA
Titolo Testata:
JOURNAL OF APPLIED PHYSIOLOGY
fascicolo: 1, volume: 90, anno: 2001,
pagine: 308 - 316
SICI:
8750-7587(200101)90:1<308:RCREBS>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
STATIC MUSCULAR-CONTRACTION; SLOW CONDUCTION-VELOCITY; GROUP-IV AFFERENTS; GROUP-III; BLOOD-PRESSURE; CAT; STIMULATION; DISCHARGE; EXERCISE; HINDLIMB;
Keywords:
exercise presser reflex; muscle contraction; muscle stretch;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
26
Recensione:
Indirizzi per estratti:
Indirizzo: Mitchell, JH Univ Texas, SW Med Ctr, Dept Internal Med, 5323 Harry Hines Blvd, Dallas, TX 75390 USA Univ Texas 5323 Harry Hines Blvd Dallas TX USA 75390 5390 USA
Citazione:
B.G. Leshnower et al., "Reflex cardiovascular responses evoked by selective activation of skeletalmuscle ergoreceptors", J APP PHYSL, 90(1), 2001, pp. 308-316

Abstract

It is well known that the exercise presser reflex (EPR) is mediated by group III and IV skeletal muscle afferent fibers, which exhibit unique discharge responses to mechanical and chemical stimuli. Based on the difference indischarge patterns of group III and IV muscle afferents, we hypothesized that activation of mechanically sensitive (MS) fibers would evoke a different pattern of cardiovascular responses compared with activation of both MS and chemosensitive (CS) fibers. Experiments were conducted in chloralose-urethane-anesthetized cats (n = 10). Passive muscle stretch was used to activate MS afferents, and electrically evoked contraction of the triceps surae was used to activate both MS and CS muscle afferents. No significant differences were shown in reflex heart rate and mean arterial pressure (MAP) responses between passive muscle stretch and evoked muscle contraction. However,when the reflex responses were matched according to tension-time index (TTI), the peak MAP response (67 +/- 4 vs. 56 +/- 4 mmHg, P < 0.05) was significantly greater at higher TTI (427 +/- 18 vs. 304 +/- 13 kg.s, high vs. lowTTI, P < 0.05), despite different modes of afferent fiber activation. Whenthe same mode of afferent fiber activation was compared, the peak MAP response (65 +/- 7 vs. 55 +/- 5 mmHg, P < 0.05) was again predicted by the magnitude of TTI (422 +/- 24 vs. 298 +/- 19 kg.s, high vs. low TTI, P < 0.05). Total sensory input from skeletal muscle ergoreceptors, as predicted by TTIand not the modality of afferent fiber activation (muscle contraction vs. passive stretch), is suggested to be the primary determinant of the magnitude of the EPR-evoked cardiovascular response.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/04/20 alle ore 01:49:39