The effect of phoneutria nigriventer venom (pnv) on rat vagus nerve in vitro (2001)
- Authors:
- Autor USP: NUCCI, GILBERTO DE - ICB
- Unidade: ICB
- Assunto: FARMACOLOGIA
- Language: Inglês
- Abstract: Objetivo: PNV causes pain and oedema in man and promotes neurogenic oedema formation in rat skin (Eur. J. Pharmacol. 391:305, 2000). To test whether PNV contains a chemical activator of sensory C-fibres we used the grease-gap technique to compare the actions of PNV with those of capsaicin on the rat vagus nerve. Métodos e Resultados: Male Wistar rats were killed humanely and the excised nerves were placed in buffer (mM): 130 NaCl, 1 CaCl2, 1 MgCl2, 3 KCl, 11 glucose, 5 HEPES; pH 7.4. The nerves were desheathed and transferred to grease-gap recording chambers. The D.C. potential between the ends of the nerve was measured using extracellular Ag/AgCl electrodes. PNV depolarised the nerve (0.18±0.3, 0.27±0.07 and 0.62±0.13 mV at 0.3, 3 and 10 mg/ml respectively, n=11). Homologous desensitisation was not observed when PNV (10 mg/ml) was re-applied 30 min after the first application. At 0.3 mM capsaicin depolarized the nerve (0.63±0.10 mV, n=5) but had no effect on subsequent PNV responses but at 5 mM, capsaicin desensitised the nerve to subsequent application of PNV. Ruthenium red (n=5) inhibited capsaicin (0.3 mM) responses (from 0.55±0.16 mV to 0.49±0.13, 0.26±0.13* and 0.17±0.05* mV at 1, 3 and 10 mM, respectively) but did not reduce PNV responsesTetrodotoxin (n=4) blocked the PNV depolarisation (from 0.30±0.05 mV to 0.18±0.02, 0.15±0.05 and 0.05±0.03* mV at 1, 3 and 10 mM, respectively) but had no effect on capsaicin responses. The 5-HT4 receptor antagonistRS39604 (n=7) abolished the PNV depolarisation (from 0.61±0.11 mV to 0.23±0.09* and 0.07±0.02* mV at 1 and 10 mM respectively) and significantly inhibited 5-HT (3 mM, n = 5) responses (from 0.71±0.06 mV to 0.46±0.04* and 0.39±0.07* mV, respectively). Both veratridine (30 mM) and KCl (10 mM)-induced depolarisation were unaffected by RS39604. Conclusões: In the vagus nerve the PNV-induced response involves activation of Na+ channels and 5-HT4 receptors. The lack of effect of PNV after a high capsaicin concentration suggests that the venom acts on capsaicin-sensitive C-fibres. The evidence indicates that PNV contains a previously unidentified 5-HT4 agonist that may have functional relevance in mediating the pain observed after spider bites
- Imprenta:
- Publisher: Federação de Sociedades de Biologia Experimental
- Publisher place: Caxambu
- Date published: 2001
- Source:
- Título do periódico: Resumos
- Conference titles: Reunião Anual da Federação de Sociedades de Biologia Experimental - FeSBE
-
ABNT
COSTA, Soraia Katia Pereira et al. The effect of phoneutria nigriventer venom (pnv) on rat vagus nerve in vitro. 2001, Anais.. Caxambu: Federação de Sociedades de Biologia Experimental, 2001. . Acesso em: 23 abr. 2024. -
APA
Costa, S. K. P., De Nucci, G., Brain, S. D., Docherty, R. J., & Antunes, E. (2001). The effect of phoneutria nigriventer venom (pnv) on rat vagus nerve in vitro. In Resumos. Caxambu: Federação de Sociedades de Biologia Experimental. -
NLM
Costa SKP, De Nucci G, Brain SD, Docherty RJ, Antunes E. The effect of phoneutria nigriventer venom (pnv) on rat vagus nerve in vitro. Resumos. 2001 ;[citado 2024 abr. 23 ] -
Vancouver
Costa SKP, De Nucci G, Brain SD, Docherty RJ, Antunes E. The effect of phoneutria nigriventer venom (pnv) on rat vagus nerve in vitro. Resumos. 2001 ;[citado 2024 abr. 23 ] - Presence of nitric oxide synthase inhibitor activity in rat pleural exsudates
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