Navegando por Palavras-chave "tail-flick test"

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    Analgesia and c-Fos expression in the periaqueductal gray induced by electroacupuncture at the Zusanli point in rats
    (Elsevier B.V., 2003-05-30) Medeiros, M. A. de; Canteras, N. S.; Suchecki, D.; Mello, LEAM; Univ Fed Rural Rio de Janeiro; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)
    The need to use anaesthetised or restrained animals in acupuncture research in laboratory animals may represent a confounding variable, since both anaesthesia and stress alter the pain threshold and the activity of pain-related brain areas. in the current study we assessed the participation of the periaqueductal gray (PAG) in electroacupuncture's (EA) analgesic effects applied to the Zusanli point (36S) under carefully controlled stress conditions. Repeated immobilisation protocols (6 days, 1 h/day and 13 days, 2 h/day) were used to diminish the influence of acute immobilisation stress on c-Fos expression and analgesia (tail-flick test) induced by electroacupuncture on the 36S point (EA36S). Animals submitted to immobilisation alone (IMMO) or to electroacupuncture (100 Hz, 2-4 V, faradic wave) on a non-point region (EANP) were compared with animals submitted to electroacupuncture on the 36S point. in animals not previously submitted to repeated immobilisation, electroacupuncture on the 36S point induced analgesia and c-Fos expression in the PAG was not different from that induced by electroacupuncture at a non-acupuncture point. in animals submitted to repeated immobilisation (repeated immobilisation for 6 days or repeated immobilisation for 13 days), however, electroacupuncture on point 36S led to higher levels of analgesia and c-Fos expression, specifically in the ventrolateral PAG (v1PAG), as compared with animal groups subjected only to immobilisation or to electroacupuncture on a non-point. Our findings endorse previous results, and point to a specific part of the PAG involved in the effects of electroacupuncture at the Zusanli point. (C) 2003 Elsevier Science B.V. All rights reserved.
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    ANGIOTENSIN (5-8) MODULATES NOCICEPTION AT the RAT PERIAQUEDUCTAL GRAY VIA the NO-sGC PATHWAY and AN ENDOGENOUS OPIOID
    (Elsevier B.V., 2013-02-12) Guethe, L. M.; Pelegrini-da-Silva, A.; Borelli, K. G.; Juliano, M. A. [UNIFESP]; Pelosi, G. G.; Pesquero, J. B. [UNIFESP]; Silva, C. L. M.; Correa, F. M. A.; Murad, F.; Prado, W. A.; Martins, A. R.; Universidade de São Paulo (USP); Univ Fed Triangulo Mineiro; Universidade Federal de São Paulo (UNIFESP); Universidade Federal do Rio de Janeiro (UFRJ); George Washington Univ; Universidade Estadual de Londrina (UEL)
    Angiotensins (Angs) modulate blood pressure, hydro-electrolyte composition, and antinociception. Although Ang (5-8) has generally been considered to be inactive, we show here that Ang (5-8) was the smallest Ang to elicit dose-dependent responses and receptor-mediated antinociception in the rat ventrolateral periaqueductal gray matter (vlPAG). Ang (5-8) antinociception seems to be selective, because it did not alter blood pressure or act on vascular or intestinal smooth muscle cells. the non-selective Ang-receptor (Ang-R) antagonist saralasin blocked Ang (5-8) antinociception, but selective antagonists of Ang-R types I, II, IV, and Mas did not, suggesting that Ang (5-8) may act via an unknown receptor. Endopeptidase EP 24.11 and amastatin-sensitive aminopeptidase from the vlPAG catalyzed the synthesis (from Ang II or Ang III) and inactivation of Ang (5-8), respectively. Selective inhibitors of neuronal-nitric oxide (NO) synthase, soluble guanylyl cyclase (sGC) and a nonselective opioid receptor (opioid-R) inhibitor blocked Ang (5-8)-induced antinociception. in conclusion, Ang (5-8) is a new member of the Ang family that selectively and strongly modulates antinociception via NO-sGC and endogenous opioid in the vlPAG. (c) 2012 IBRO. Published by Elsevier B.V. All rights reserved.