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Titolo:
Myogenic reactivity of rat epineurial arterioles: potential role in local vasoregulatory events
Autore:
Wang, HX; Davis, MJ; Rajanayagam, MAS; Potocnik, SJ; Hill, MA;
Indirizzi:
RMIT Univ, Dept Human Biol & Movement Sci, Microvasc Biol Grp, Bundoora, Vic 3083, Australia RMIT Univ Bundoora Vic Australia 3083 Grp, Bundoora, Vic 3083, Australia Texas A&M Univ, Coll Med, Dept Med Physiol, College Stn, TX 77843 USA Texas A&M Univ College Stn TX USA 77843 hysiol, College Stn, TX 77843 USA
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
fascicolo: 1, volume: 46, anno: 1999,
pagine: H144 - H151
SICI:
0363-6135(199907)46:1<H144:MROREA>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
NERVE BLOOD-FLOW; EXPERIMENTAL DIABETIC NEUROPATHY; SCIATIC-NERVE; SKELETAL-MUSCLE; ADRENERGIC-INNERVATION; PERIPHERAL-NERVE; NEUROPEPTIDE-Y; VASA-NERVORUM; PRESSURE; VESSELS;
Keywords:
autoregulation; myogenic reactivity; vasa nervorum;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Hill, MA RMIT Univ, Dept Human Biol & Movement Sci, Microvasc Biol Grp, Bundoora, Vic 3083, Australia RMIT Univ Bundoora Vic Australia 3083 doora, Vic 3083, Australia
Citazione:
H.X. Wang et al., "Myogenic reactivity of rat epineurial arterioles: potential role in local vasoregulatory events", AM J P-HEAR, 46(1), 1999, pp. H144-H151

Abstract

Local control of neural blood flow is considered to reside in innervation of epineurial and endoneurial arterioles rather than in intrinsic autoregulatory mechanisms. With the use of an isolated vessel preparation and an in vivo approach, the present studies examined intrinsic vasomotor responsiveness of epineurial arterioles. Segments of epineurial arterioles, cannulatedon glass micropipettes (40 mu m) and pressurized in the absence of intraluminal flow, showed sustained pressure-dependent (30-90 mmHg) vasoconstriction and acute myogenic reactivity. Myogenic tone was unaffected by phentolamine (10(-6) M). Removal of extracellular Ca2+ resulted in loss of spontaneous tone and passive behavior. Concentration-response curves for norepinephrine (10(-9)-3 x 10(-6) M) and relaxation to both acetylcholine (10(-8)-10(-5) M) and adenosine (10(-8)-10(-4) M) were obtained. Acetylcholine dilator responses were inhibited by NG-nitro-L-arginine methyl ester. Epineurial blood flow was measured in vivo using a laser-Doppler flow probe. Blood flow declined over a 2-h period after surgery, and during this time preparationsdeveloped responsiveness to the dilator acetylcholine. Phentolamine blocked vasoconstrictor responses to exogenous norepinephrine but only partially reversed the in vivo baseline tone. The time-dependent decline in epineurial blood flow was observed despite the presence of tetrodotoxin (1 mu M), further confirming that tone was predominantly caused by myogenic rather thanneurogenic mechanisms. It is concluded that because epineurial arterioles exhibit intrinsic myogenic reactivity, they have the potential to participate in local regulation of neural hemodynamics independently of their own innervation.

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Documento generato il 08/07/20 alle ore 06:24:34