A spider derived peptide, PnPP-19, induces central antinociception mediated by opioid and cannabinoid systems

Some peptides purified from the venom of the spider Phoneutria nigriventer have been identified as potential sources of drugs for pain treatment. In this study, we characterized the antinociceptive effect of the peptide PnPP-19 on the central nervous system and investigated the possible involvement of opioid and cannabinoid systems in its action mechanism. Methods Nociceptive threshold to thermal stimulation was measured according to the tail-flick test in Swiss mice. All drugs were administered by the intracerebroventricular route. Results PnPP-19 induced central antinociception in mice in the doses of 0.5 and 1 g. The non-selective opioid receptor antagonist naloxone (2.5 and 5 g), -opioid receptor antagonist clocinnamox (2 and 4 g), -opioid receptor antagonist naltrindole (6 and 12 g) and CB1 receptor antagonist AM251 (2 and 4 g) partially inhibited the antinociceptive effect of PnPP-19 (1 g). Additionally, the anandamide amidase inhibitor MAFP (0.2 g), the anandamide uptake inhibitor VDM11 (4 g) and the aminopeptidase inhibitor bestatin (20 g) significantly enhanced the antinociception induced by a low dose of PnPP-19 (0.5 g). In contrast, the -opioid receptor antagonist nor-binaltorphimine (10 g and 20 g) and the CB2 receptor antagonist AM630 (2 and 4 g) do not appear to be involved in this effect. Conclusions PnPP-19-induced central antinociception involves the activation of CB1 cannabinoid, - and -opioid receptors. Mobilization of endogenous opioids and cannabinoids might be required for the activation of those receptors, since inhibitors of endogenous substances potentiate the effect of PnPP-19. Our results contribute to elucidating the action of the peptide PnPP-19 in the antinociceptive pathway.

Tarantula cubensis extract alters the degree of apoptosis and mitosis in canine mammary adenocarcinomas

In the present study, 13 clinical cases of canine mammary adenocarcinoma were evaluated in order to understand the effect of Tarantula cubensis extract (TCE) on tumor tissue. Punch biopsies were taken from the tumors before treatment with TCE. Subcutaneous injections of TCE were administered three times at weekly intervals (3 mL per dog). Between days 7 and 10 after the third injection, the tumor masses were extirpated by complete unilateral mastectomy. Pre- and post-treatment tumor tissues were immunohistochemically assessed. The expression of B-cell lymphoma 2 (Bcl-2) was found to be higher in pre-treatment compared to post-treatment tissues (p 0.05). The apoptotic index was determined to be low before treatment and increased during treatment. These results suggest that TCE may be effective for controlling the local growth of canine mammary adenocarcinoma by regulating apoptosis.