Evidence for a role of capsaicin-sensitive sensory nerves in the lung oedema induced by Tityus serrulatus venom in rats.
In the most severe cases of human envenoming by Tityus serrulatus, pulmonary oedema is a frequent finding and can be the cause of death. We have previously demonstrated a role for neuropeptides acting on tachykinin NK(1) receptors in the development of lung oedema following i.v. injection of T. serrulatus venom (TsV) in experimental animals. The present work was designed to investigate whether capsaicin-sensitive primary afferent neurons were a potential source of NK(1)-acting neuropeptides. To this end, sensory nerves were depleted of neuropeptides by neonatal treatment of rats with capsaicin. The effectiveness of this strategy at depleting sensory nerves was demonstrated by the inhibition of the neuropeptide-dependent response to intraplantar injection of formalin. Pulmonary oedema, as assessed by the levels of extravasation of Evans blue dye in the bronchoalveolar lavage and in the left lung, was markedly inhibited in capsaicin-treated animals. In contrast, capsaicin treatment failed to alter the increase in arterial blood pressure or the lethality following i.v. injection of TsV. Our results demonstrate an important role for capsaicin-sensitive sensory nerves in the cascade of events leading to lung injury following the i.v. administration of TsV.
Andrade
Marcus V M
MV
Department of Surgery, Faculdade de Medicine, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 Pampulha, 31270-901, Belo Horizonte, Minas Gerais, Brazil.
Souza
Danielle G
DG
de A Castro
Maria Salete
MS
Cunha-Melo
José R
JR
Teixeira
Mauro M
MM
D000818:Animals; D002211:Capsaicin / Q000008:administration & dosage / Q000494:pharmacology*; D007275:Injections, Intravenous; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology; D011654:Pulmonary Edema / Q000209:etiology* / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D018039:Receptors, Tachykinin / Q000187:drug effects / Q000502:physiology; D012604:Scorpion Venoms / Q000494:pharmacology / Q000633:toxicity*; D012605:Scorpions
D018039:Receptors, Tachykinin; D012604:Scorpion Venoms; D002211:Capsaicin