Exercise training normalizes an increased neuronal excitability of NTS-projecting neurons of the hypothalamic paraventricular nucleus in hypertensive rats


Autoria(s): Stern, Javier E.; Sonner, Patrick M.; Son, Sook Jin; Silva, Fabiana C. P.; Jackson, Keshia; Michelini, Lisete C.
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

21/10/2013

21/10/2013

2012

Resumo

Stern JE, Sonner PM, Son SJ, Silva FC, Jackson K, Michelini LC. Exercise training normalizes an increased neuronal excitability of NTS-projecting neurons of the hypothalamic paraventricular nucleus in hypertensive rats. J Neurophysiol 107: 2912-2921, 2012. First published February 22, 2012; doi:10.1152/jn.00884.2011.-Elevated sympathetic outflow and altered autonomic reflexes, including impaired baroreflex function, are common findings observed in hypertensive disorders. Although a growing body of evidence supports a contribution of preautonomic neurons in the hypothalamic paraventricular nucleus (PVN) to altered autonomic control during hypertension, the precise underlying mechanisms remain unknown. Here, we aimed to determine whether the intrinsic excitability and repetitive firing properties of preautonomic PVN neurons that innervate the nucleus tractus solitarii (PVN-NTS neurons) were altered in spontaneously hypertensive rats (SHR). Moreover, given that exercise training is known to improve and/or correct autonomic deficits in hypertensive conditions, we evaluated whether exercise is an efficient behavioral approach to correct altered neuronal excitability in hypertensive rats. Patch-clamp recordings were obtained from retrogradely labeled PVN-NTS neurons in hypothalamic slices obtained from sedentary (S) and trained (T) Wistar-Kyoto (WKY) and SHR rats. Our results indicate an increased excitability of PVN-NTS neurons in SHR-S rats, reflected by an enhanced input-output function in response to depolarizing stimuli, a hyperpolarizing shift in Na+ spike threshold, and smaller hyperpolarizing afterpotentials. Importantly, we found exercise training in SHR rats to restore all these parameters back to those levels observed in WKY-S rats. In several cases, exercise evoked opposing effects in WKY-S rats compared with SHR-S rats, suggesting that exercise effects on PVN-NTS neurons are state dependent. Taken together, our results suggest that elevated preautonomic PVN-NTS neuronal excitability may contribute to altered autonomic control in SHR rats and that exercise training efficiently corrects these abnormalities.

National Heart, Lung, and Blood Institute [R01 HL085767]

Fundacao de Amparo a Pesquisa do Estado de Sao Paulo Research [02/11937-9, 06/50548-9]

Identificador

JOURNAL OF NEUROPHYSIOLOGY, BETHESDA, v. 107, n. 10, pp. 2912-2921, MAY, 2012

0022-3077

http://www.producao.usp.br/handle/BDPI/35411

10.1152/jn.00884.2011

http://dx.doi.org/10.1152/jn.00884.2011

Idioma(s)

eng

Publicador

AMER PHYSIOLOGICAL SOC

BETHESDA

Relação

JOURNAL OF NEUROPHYSIOLOGY

Direitos

closedAccess

Copyright AMER PHYSIOLOGICAL SOC

Palavras-Chave #EXERCISE #HYPOTHALAMIC PREAUTONOMIC NEURONS #NUCLEUS TRACTUS SOLITARII #ROSTRAL VENTROLATERAL MEDULLA #SYMPATHETIC-NERVE ACTIVITY #CEREBELLAR PURKINJE NEURONS #ARTERIAL BAROREFLEX CONTROL #BARORECEPTOR REFLEX CONTROL #PRESYMPATHETIC PVN NEURONS #PRE-AUTONOMIC NEURONS #HEART-RATE #BLOOD-PRESSURE #TRACTUS-SOLITARIUS #NEUROSCIENCES #PHYSIOLOGY
Tipo

article

original article

publishedVersion