Afferent signaling drives oxytocinergic preautonomic neurons and mediates training-induced plasticity

Autor(es)

Cavalleri, Marina T. ^[1] ; Burgi, Katia ^[1] ; Cruz, Josiane C. ^[1] ; Jordao, Maria T. ^[1] ; Ceroni, Alexandre ^[1] ; Michelini, Lisete C. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Physiol & Biophys, Inst Biomed Sci, BR-05508000 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY; v. 301, n. 4, p. R958-R966, OCT 2011.
• Citações Web of Science: 20

Resumo

Cavalleri MT, Burgi K, Cruz JC, Jordao MT, Ceroni A, Michelini LC. Afferent signaling drives oxytocinergic preautonomic neurons and mediates training-induced plasticity. Am J Physiol Regul Integr Comp Physiol 301: R958-R966, 2011. First published July 27, 2011; doi:10.1152/ajpregu.00104.2011.-We showed previously that oxytocinergic (OTergic) projections from the hypothalamic paraventricular nucleus (PVN) to the dorsal brain stem mediate traininginduced heart rate (HR) adjustments and that beneficial effects of training are blocked by sinoaortic denervation (SAD; Exp Physiol 94: 630-640; 1103-1113, 2009). We sought now to determine the combined effect of training and SAD on PVN OTergic neurons in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. Rats underwent SAD or sham surgery and were trained (55% of maximal capacity) or kept sedentary for 3 mo. After hemodynamic measurements were taken at rest, rats were deeply anesthetized. Fresh brains were frozen and sliced to isolate the PVN; samples were processed for OT expression (real-time PCR) and fixed brains were processed for OT immunofluorescence. In sham rats, training improved treadmill performance and increased the gain of baroreflex control of HR. Training reduced resting HR (-8%) in both groups, with a fall in blood pressure (-10%) only in SHR rats. These changes were accompanied by marked increases in PVN OT mRNA expression (3.9-and 2.2-fold in WKY and SHR rats, respectively) and peptide density in PVN OTergic neurons (2.6-fold in both groups), with significant correlations between OT content and training- induced resting bradycardia. SAD abolished PVN OT mRNA expression and markedly reduced PVN OT density in WKY and SHR. Training had no effect on HR, PVN OT mRNA, or OT content following SAD. The chronic absence of inputs from baroreceptors and chemoreceptors uncovers the pivotal role of afferent signaling in driving both the plasticity and activity of PVN OTergic neurons, as well as the beneficial effects of training on cardiovascular control. (AU)

• Processo FAPESP: 07/53320-1 - Ajustes da atividade simpatica periferica promovidos pelo treinamento fisico em normotensos e hipertensos: efeitos da remocao seletiva dos baroreceptores arteriais.
• Beneficiário: Katia Burgi
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 09/54299-1 - Efeitos da remoção seletiva dos barorreceptores arteriais sobre a expressão e funcionalidade de projeções vasopressinergicas e ocitocinérgicas ao bulbo dorsal e ventral sobre o controle autonômico
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• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 08/53961-0 - Efeitos sequenciais do treinamento físico e do treinamento físico associado à hipertensão sobre a plasticidade neuronal em vias autonômicas centrais
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