Navegando por Palavras-chave "BLOOD PRESSURE"

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    CARDIOVASCULAR ADJUSTMENTS IN LIMB RETRACTION PROVOKED BY NOXIOUS-STIMULATION IN DECEREBRATE AND SPINAL CATS - EVIDENCE FOR A SOMATOTOPIC ORGANIZATION
    (Assoc Bras Divulg Cientifica, 1995-03-01) Cravo, Sergio Luiz [UNIFESP]; Lopes, Oswaldo Ubriaco [UNIFESP]; Fraga, CAB; Timo-Iaria, César [UNIFESP]; FAC CIENCIAS MED SAO PAULO; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    Arterial blood pressure, heart rate and iliac blood flow were continuously recorded in 61 adult cats and their alteration induced by noxious stimulation of the interdigital spaces of the four limbs was studied in intact (anesthetized) and in decerebrate and spinal preparations. Noxious stimulation of any limb in the decerebrate animals provoked retraction 61% of the times and an increase of blood pressure and heart rate in approximately 80% of the stimulations. Stimulation of a hindlimb provoked an increase of blood flow in the same limb in about 80% of the stimulations, due to active vasodilation. Contralateral stimulation provoked a smaller increase of blood flow but with an increase in vascular resistance, indicating some degree of vasoconstriction. Stimulation of the forelimbs induced small increases of blood flow in the hindlimbs but the calculated vascular resistance was higher than the basal values, also indicating vasoconstriction. Neuromuscular blockade with gallamine did not affect the increase of hindlimb blood flow, suggesting a central regulation of the intricate distribution of blood to the limbs. The vasodilation was not due to activation of sympathetic cholinergic vasodilator neurons inasmuch as the blood flow responses were not affected by cholinergic blockade with atropine. In spinal animals, stimulation of any limb provoked small increases of blood pressure, extremely low degrees of tachycardia and an increase of hindlimb blood flow, with active vasodilation. Neuromuscular paralysis, however, abolished the adjustments of blood flow in the hindlimbs, indicating that metabolites and/or sensory information caused by muscle contraction induced them. In intact cats anesthetized with sodium pentobarbiturate, blood pressure and heart rate increased under noxious stimulation, although less than in the decerebrate animals. Nearly 40% of the stimulations provoked hypotension rather than hypertension. Blood flow increased due to stimulation of any limb but, as in the decerebrate preparation, there was active vasodilation in the ipsilateral hindlimb and vasoconstriction in the contralateral one.
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    Localization of central pressor action of bradykinin in medulla oblongata
    (Amer Physiological Soc, 1993-09-01) Fior, Debora Rejane [UNIFESP]; Martins, Domingos Tabajara de Oliveira [UNIFESP]|Lindsey, Charles Julian [UNIFESP]; UNIV FED MATO GROSSO; Universidade Federal de São Paulo (UNIFESP)
    The intracerebroventricular injection of bradykinin produces an increase in arterial blood pressure. The site of action for this effect has been reported to be in the lateral septal area, in the hypothalamus, or in the ventral portion of the third ventricle. Bradykinin injected into the fourth cerebral ventricle of unanesthetized rats produced a pressor effect with a shorter latency and a larger maximal effect than when injected in the third or lateral ventricles. Bradykinin in the fourth ventricle was also 10 times more potent than in the third ventricle and 100 times more potent than in the lateral ventricle. No changes in blood pressure were observed when bradykinin was injected into the cerebellum or in the subarachnoid space of the ventral surface of the brain or of the medulla. Microinjections in the medulla oblongata showed that the pressor responses were obtained when bradykinin was injected in the nucleus tractus solitarius or in the dorsal spinal trigeminal tract. No effect was observed after injections were given into the ventral, ventral lateral medulla, or other medullary regions. The data suggest that bradykinin may play a regulatory role in the central control of blood pressure by stimulating sites that are near the dorsal and dorsal lateral surface's of the medulla and accessible to kinins in cerebrospinal fluid and in the cerebral arterial circulation.