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Titolo:
EFFECTS OF SINOAORTIC DENERVATION ON FOS EXPRESSION IN THE BRAIN EVOKED BY HYPERTENSION AND HYPOTENSION IN CONSCIOUS RABBITS
Autore:
POTTS PD; POLSON JW; HIROOKA Y; DAMPNEY RAL;
Indirizzi:
UNIV SYDNEY,DEPT PHYSIOL SYDNEY NSW 2006 AUSTRALIA UNIV SYDNEY,DEPT PHYSIOL SYDNEY NSW 2006 AUSTRALIA
Titolo Testata:
Neuroscience
fascicolo: 2, volume: 77, anno: 1997,
pagine: 503 - 520
SICI:
0306-4522(1997)77:2<503:EOSDOF>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
C-FOS; PARABRACHIAL NUCLEUS; CARDIOVASCULAR CONTROL; LAMINA TERMINALIS; HYPERTONIC SALINE; ANGIOTENSIN-II; AREA POSTREMA; CATECHOLAMINERGIC NEURONS; SUSTAINED HYPERTENSION; SODIUM-NITROPRUSSIDE;
Keywords:
ARTERIAL PRESSURE; BARORECEPTOR REFLEX; CENTRAL CARDIOVASCULAR PATHWAYS; NUCLEUS OF THE SOLITARY TRACT; VENTROLATERAL MEDULLA; IMMEDIATE EARLY GENES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
66
Recensione:
Indirizzi per estratti:
Citazione:
P.D. Potts et al., "EFFECTS OF SINOAORTIC DENERVATION ON FOS EXPRESSION IN THE BRAIN EVOKED BY HYPERTENSION AND HYPOTENSION IN CONSCIOUS RABBITS", Neuroscience, 77(2), 1997, pp. 503-520

Abstract

We have previously shown [Li and Dampney (1994) Neuroscience 61, 613-634] that periods of sustained hypertension and hypotension each induces a distinctive and reproducible pattern of neuronal expression of Fos (a marker of neuronal activation) in specific regions of the brainstem and forebrain of conscious rabbits. The aim of this study was to determine the contribution of afferent inputs from arterial baroreceptors to the activation of neurons in these various brain regions that is caused by a sustained change in arterial pressure. Experiments were carried out on rabbits in which the carotid sinus and aortic depressor nerves were cut in a preliminary operation. Following a recovery periodof seven to 10 days, a moderate hypertension or hypotension (increaseor decrease in arterial pressure of 20-30 mmHg) was induced in conscious barodenervated rabbits for 60 min by the continuous infusion of phenylephrine or sodium nitroprusside, respectively. In control experiments, barodenervated rabbits were subjected to the identical proceduresexcept that they were infused with the vehicle solution alone. Compared with the effects seen in barointact rabbits, [Li and Dampney (1994)Neuroscience 61, 613-634] the number of neurons that expressed Fos inresponse to hypertension was reduced by approximately 90% in the nucleus of the solitary tract and in the caudal and intermediate parts of the ventrolateral medulla. In supramedullary regions, baroreceptor denervation resulted in a reduction of approximately 60% in hypertension-induced Fos expression in the central nucleus of the amygdala and in the bed nucleus of the stria terminalis, but no significant reduction in the parabrachial complex in the pons. Following hypotension, the number of neurons that expressed Fos in barodenervated rabbits, compared with barointact rabbits, [Li and Dampney (1994) Neuroscience 61, 613-634] was reduced by approximately 90%, in the nucleus of the solitary tract, area postrema, and caudal, intermediate and rostral parts of theventrolateral medulla. Baroreceptor denervation also resulted in a similar large reduction in hypotension-induced Fos expression in many supramedullary regions (locus coeruleus, midbrain periaqueductal grey, hypothalamic paraventricular nucleus, and in the central nucleus of theamygdala and the bed nucleus of the stria terminalis in the basal forebrain). In the supraoptic nucleus, hypotension-induced Fos expressionin barodenervated rabbits was reduced by 75% compared to barointact animals, but was still significantly greater than in control animals. There was also a high level of Fos expression, much greater than in control animals, in the circumventricular organs surrounding the third ventricle (subfornical organ and organum vasculosum lamina terminalis). The results indicate that in conscious rabbits the activation of neurons that occurs in several discrete regions at all levels of the brain following a sustained change in arterial pressure is largely dependentupon inputs from arterial baroreceptors, with the exception of neurons in the circumventricular organs surrounding the third ventricle thatare activated by sustained hypotension. The latter group of neurons are known to project to vasopressin-secreting neurons in the supraopticnucleus, and may therefore via this pathway trigger the hypotension-induced release of vasopressin that occurs in tile absence of baroreceptor inputs. (C) 1997 IBRO.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 06/04/20 alle ore 01:20:06