Alpha2-adrenergic, gabaergic or opioidergic activation in the lateral parabrachial nucleus (LPBN) increases sodium intake. In the present study, we investigated the effects of single or combined block-ade of opioidergic and gabaergic receptors in the LPBN on the increase of 0.3 M NaCl intake induced by _2-adrenoceptor activation in the LPBN. Male Holtzman rats (n = 5–9/group) with cannulas implanted bilaterally...
Inhibitory mechanisms in the lateral parabrachial nucleus (LPBN) and central GABAergic mechanisms are involved in the regulation of water and NaCl intake. Besides increasing fluid depletion-induced sodium intake, the activation of GABAA receptors with muscimol into the LPBN also induces ingestion of 0.3 M NaCl in normonatremic, euhydrated rats. It has been suggested that inhibitory mechanisms activated by osmot...
Hydrogen peroxide (H2O2), important reactive oxygen species produced endogenously, may have different physiological actions. The superoxide anion (O2 •_) is suggested to be part of the signaling mechanisms activated by angiotensin II (ANG II) and central virus-mediated overexpression of the enzyme superoxide dismutase (that dismutates O2 •_ to H2O2) reduces pressor and dipsogenic responses to central ANG II. Wh...
Reactive oxygen species (ROS) have been shown to modulate neuronal synaptic transmission and may play a role on the autonomic control of the cardiovascular system. In this study we investigated the effects produced by hydrogen peroxide (H2O2) injected alone or combined with the anti-oxidant agent N-acetil-l-cysteine (NAC) or catalase into the fourth brain ventricle (4th V) on mean arterial pressure and heart ra...
GABAA and GABAB receptors are present in the lateral parabrachial nucleus (LPBN), a pontine area involved with inhibitory mechanisms related to the control of sodium appetite. Activation of GABAA receptors in the LPBN induces strong ingestion of 0.3 M sodium chloride (NaCl) in normonatremic and euhydrated rats. In the present study, we investigated the effects of the GABAB receptor agonist baclofen, injected al...
GABAergic activation in the lateral parabrachial nucleus (LPBN) induces sodium and water intake in satiated and normovolemic rats. In the present study we investigated the effects of GABAA receptor activation in the LPBN on 0.3M NaCl, water, 2% sucrose and food intake in rats submitted to sodium depletion (treatment with the diuretic furosemide subcutaneously + sodium deficient food for 24 h), 24 h food depriva...
The nucleus tractus solitarius (NTS), a major hindbrain area involved in cardiovascular regulation, receives primary afferent fibers from peripheral baroreceptors and chemoreceptors. Hydrogen peroxide (H(2)O(2)) is a relatively stable and diffusible reactive oxygen species (ROS), which acting centrally, may affect neural mechanisms. In the present study, we investigated effects of H(2)O(2) alone or combined wit...