Blockade of TRPA1 with HC-030031 attenuates visceral nociception by a mechanism independent of inflammatory resident cells, nitric oxide and the opioid system.

BACKGROUND: Some studies have shown a somatic nociceptive response due to the activation of transient receptor potential A1 channels (TRPA1), which is modulated by the TRPA1 antagonist HC-030031. However, a few studies report the role of TRPA1 in visceral pain. Therefore, we investigated the participation of TRPA1 in visceral nociception and the involvement of nitric oxide, the opioid system and resident cells in the modulation of these channels. METHODS: Mice were treated with vehicle or HC-030031 (18.75-300 mg/kg) before ifosfamide (400 mg/kg), 0.75% mustard oil (50 µL/colon), acetic acid 0.6% (10 mL/kg), zymosan (1 mg/cavity) or misoprostol (1 µg/cavity) injection. Visceral nociception was assessed through the electronic von Frey test or the writhing response. Ifosfamide-administered mice were euthanized for bladder analysis. The involvement of nitric oxide and the opioid system were investigated in mice injected with ifosfamide and mustard oil, respectively. The participation of resident peritoneal cells in acetic acid-, zymosan- or misoprostol-induced nociception was also evaluated. RESULTS: HC-030031 failed to protect animals against ifosfamide-induced bladder injury (p > 0.05). However, a marked antinociceptive effect against ifosfamide, mustard oil, acetic acid, zymosan and misoprostol was observed (p < 0.05). Neither L-arginine (600 mg/kg) nor naloxone (2 mg/kg) could reverse the antinociceptive effect of HC-030031. The reduction of the peritoneal cell population inhibited the acetic acid and zymosan-related writhes without interfering with the misoprostol effect. CONCLUSIONS: Our findings suggest that the blockade of TRPA1 attenuates visceral nociception by a mechanism independent of the modulation of resident cells, nitric oxide and opioid pathways.

On the diversity of mollusc intermediate hosts of Angiostrongylus costaricensis Morera & Cespedes, 1971 in southern Brazil.

Veronicellid slugs are considered the most important intermediate hosts of Angiostrongylus costaricensis, an intra-arterial nematode of rodents. Studies undertaken in three localities in southern Brazil led to identification of molluscs other than veronicellid slugs as hosts of A. costaricensis: Limax maximus, Limax flavus and Bradybaena similaris. These data indicate a low host specificity of larval stages of A. costaricensis, as it has been reported to other congeneric species.

Actinomicose da parede abdominal -relato de um caso. / Actinomycosis of the abdominal wall-report of a case

A actinomicose e uma doenca causada por actinomicetos do genero Actinomyces e pelo Arachnia propionica.A infeccao se apresenta mais frequentemente em sua localizacao cervico-facial, toracica e abdominal. Dentre as manifestacoes menos frequentes da actinomicose a localizacao na parede abdominal e uma das mais raras. Poucos casos de actinomicose com esta localizacao tem sido relatados (Milkov & Andreev, 1963 Depaulis & Martinet, 1964: Modrzewski & Ryder-Struska, 1967; Mousseau & Mousseau, 1973; Olsson, 1974; Minocha, Sharma & Nair 1975; Puppala & Steinheber, 1978), o que justifica a publicacao deste caso