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Titolo:
EFFECTS OF SYMPATHETIC-NERVE STIMULATION ON MEMBRANE-POTENTIAL, [CA2-MARINUS(](I) AND FORCE IN THE ARRESTED SINUS VENOSUS OF THE TOAD, BUFO)
Autore:
COUSINS HM; BRAMICH NJ;
Indirizzi:
PRINCE WALES MED RES INST,HIGH ST RANDWICK NSW 2031 AUSTRALIA UNIV MELBOURNE,DEPT ZOOL PARKVILLE VIC 3052 AUSTRALIA
Titolo Testata:
Journal of physiology
fascicolo: 2, volume: 505, anno: 1997,
pagine: 513 - 527
SICI:
0022-3751(1997)505:2<513:EOSSOM>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
INTRACELLULAR CALCIUM-RELEASE; CYCLIC ADP-RIBOSE; GUINEA-PIG; INOSITOL TRISPHOSPHATE; SARCOPLASMIC-RETICULUM; SKELETAL-MUSCLE; VENTRICULAR MYOCYTES; SINOATRIAL NODE; XENOPUS OOCYTES; NA/CA EXCHANGE;
Tipo documento:
Article
Natura:
Periodico
Citazioni:
40
Recensione:
Indirizzi per estratti:
Citazione:
H.M. Cousins e N.J. Bramich, "EFFECTS OF SYMPATHETIC-NERVE STIMULATION ON MEMBRANE-POTENTIAL, [CA2-MARINUS(](I) AND FORCE IN THE ARRESTED SINUS VENOSUS OF THE TOAD, BUFO)", Journal of physiology, 505(2), 1997, pp. 513-527

Abstract

1. The effects of sympathetic nerve stimulation on membrane potentialand on the intracellular concentration of calcium ions, [Ca2+](i), were recorded concurrently from the sinus venosus of the toad, Bufo marinus, in preparations where beating had been abolished by adding an organic calcium antagonist to the physiological saline. In a separate setof experiments the effects of sympathetic nerve stimulation on force production were examined. 2. Stimulation of the sympathetic nerves caused a membrane depolarization and a simultaneous increase in [Ca2+](i). Both responses were reduced by dihydroergotamine (20 mu M). 3. The membrane depolarization and increase in [Ca2+](i) evoked by sympatheticnerve stimulation were abolished by ryanodine (10 mu M), or caffeine (3 mM). The effects of caffeine, but not those of ryanodine, were fully reversible. 4. Although the Ca2+-ATPase inhibitor thapsigargin (30 mu M) itself had little effect on the responses to sympathetic nerve stimulation, in its presence caffeine (3 mM) irreversibly abolished the responses. 5. In the presence of nifedipine (10 mu M), sympathetic nerve stimulation caused contractions of the sinus venosus. These responses were abolished by either ryanodine (10 mu M) or caffeine (3 mM). 6. The results suggest that neuronally released transmitter activates a complex biochemical pathway which triggers the release of Ca2+ from internal stores.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/09/20 alle ore 12:05:05