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Titolo:
DIFFERENTIAL FREQUENCY-DEPENDENT REFLEX INTEGRATION OF MYELINATED ANDNONMYELINATED RAT AORTIC BARORECEPTORS
Autore:
FAN W; ANDRESEN MC;
Indirizzi:
OREGON HLTH SCI UNIV,DEPT PHYSIOL PORTLAND OR 97201 OREGON HLTH SCI UNIV,DEPT PHYSIOL & PHARMACOL PORTLAND OR 97201
Titolo Testata:
American journal of physiology. Heart and circulatory physiology
fascicolo: 2, volume: 44, anno: 1998,
pagine: 632 - 640
SICI:
0363-6135(1998)44:2<632:DFRIOM>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
SPONTANEOUSLY HYPERTENSIVE RATS; CAROTID-SINUS BARORECEPTORS; FUNCTIONALLY DIFFERENT TYPES; FIRING CHARACTERISTICS; SYMPATHETIC REFLEX; SENSORY NEURONS; AFFERENT-FIBERS; CAPSAICIN; CHEMORECEPTORS; MECHANISMS;
Keywords:
SENSORY AFFERENTS; BLOOD PRESSURE; MYELINATED AXONS; NONMYELINATED AXONS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
55
Recensione:
Indirizzi per estratti:
Citazione:
W. Fan e M.C. Andresen, "DIFFERENTIAL FREQUENCY-DEPENDENT REFLEX INTEGRATION OF MYELINATED ANDNONMYELINATED RAT AORTIC BARORECEPTORS", American journal of physiology. Heart and circulatory physiology, 44(2), 1998, pp. 632-640

Abstract

Electrical activation of myelinated (A type) and nonmyelinated (C type) baroreceptor axons (BR) in aortic depressor nerve (ADN) evoked baroreflex changes in mean arterial pressure MAP) in chloralose-urethan-anesthetized rats. Low Stimulation intensities (<3 V) activated only A-type BR electroneurograms (ENG). A-type selective stimulus trains required minimum frequencies >10 Hz to evoke reflex MAP decreases, and the largest MAP responses occurred at 50 Hz and higher In contrast, high stimulation intensities (18-20 V) maximally activated two volleys in ADN ENG corresponding to A- and C-type BR volleys. High-intensity trainsdecreased MAP at low frequency (1 Hz) and largest reflex responses atgreater than or equal to 5 Hz. Capsaicin (Cap) applied periaxonally to ADN selectively blocked C-type ENG volleys but not A-type volleys. Reflex curves with supramaximal intensity during Cap were indistinguishable from the pre-Cap block of the C-fiber volley (ED50) = 200 nM) without significant attenuation of the A-type volley below 1 mu M. However, 100 mu M Cap blocked conduction in all myelinated vagal axons as well as C-type axons. Thus Cap is selective for sensory C-type axons only at low micromolar concentrations. Myelinated and non-myelinated arterial BR evoke characteristically different frequency-response reflex relations that suggest distinct differences in sensory information processing mechanisms.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 14/08/20 alle ore 17:03:27