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Chu K.-M.,Emesis Research Group | Ngan M.-P.,Emesis Research Group | Wai M.-K.,Emesis Research Group | Yeung C.-K.,Emesis Research Group | And 4 more authors.
Toxicology Letters | Year: 2010

Pungent transient receptor potential vanilloid (TRPV1) channel activators have been shown to have broad inhibitory anti-emetic activity against centrally- and peripherally acting challenges but only at doses that have adverse effects on the cardiovascular system and on temperature homeostasis. In the present studies, we investigated the anti-emetic potential of the non-pungent TRPV1 activator, olvanil (0.05-5 mg/kg, s.c., 3 times per day, for 3 days) to antagonise the acute and delayed emesis induced by cisplatin (5 mg/kg, i.p.) in ferrets that had been implanted with radiotelemetry devices to enable an analysis of heart rate and temperature. Cisplatin induced an acute (day 1: 48.0 ± 18.3 retches + vomits) and delayed (day 2: 111.7 ± 35.5; day 3: 147.5 ± 20.2 retches + vomits) emetic response that was associated with reduced food (-98.7% at day 3, P < 0.001) and water consumption (-70.2% at day 3, P < 0.001) and progressive weight loss (-12.0% at day 3, P < 0.001). Olvanil did not prevent either emesis or the weight loss and negative effects on food and water consumption (P > 0.05); the effect on food consumption appeared potentiated by a further 21.2% at 0.05 mg/kg (P < 0.05) and 19.9% at 0.5 mg/kg (P < 0.05). Cisplatin did not alter body temperature (basal: 37.7 ± 0.1 °C) or heart rate (basal: 233.7 ± 5.5 beats per min (BPM); P > 0.05), but hypothermia (-1.6 °C) and increases in locomotor activity (50-90%) were recorded in animals concomitantly treated with olvanil (P < 0.05). These data indicate that non-pungent activators as exemplified by olvanil are unlikely to be useful clinically for the control of the gastrointestinal side effects induced by cisplatin. © 2009 Elsevier Ireland Ltd. All rights reserved.


Chu K.-M.,Emesis Research Group | Ngan M.-P.,Emesis Research Group | Wai M.-K.,Emesis Research Group | Yeung C.-K.,Emesis Research Group | And 5 more authors.
Neuropharmacology | Year: 2010

Anti-emetic drugs such as the tachykinin NK1 receptor antagonists are useful to control emesis induced by diverse challenges. Evidence suggests pungent capsaicin-like TRPV1 activators also have broad inhibitory anti-emetic activity. However, pungent compounds are associated with undesirable effects including adverse actions on the cardiovascular system and on temperature homeostasis. In the present investigations using the ferret, we examine if the non-pungent vanilloid, olvanil, has useful anti-emetic properties without adversely affecting behaviour, blood pressure or temperature control. Olvanil (0.05-5 mg/kg, s.c.) was compared to the pungent vanilloid, resiniferatoxin (RTX; 0.1 mg/kg, s.c.), and to the anandamide reuptake inhibitor, AM404 (10 mg/kg, s.c.), for a potential to inhibit emesis induced by apomorphine (0.25 mg/kg, s.c.), copper sulphate (50 mg/kg, intragastric), and cisplatin (10 mg/kg, i.p.). Changes in blood pressure and temperature were also recorded using radiotelemetry implants. In peripheral administration studies, RTX caused transient hypertension, hypothermia and reduced food and water intake, but also significantly inhibited emesis induced by apomorphine, copper sulphate, or cisplatin. Olvanil did not have a similar adverse profile, and antagonised apomorphine- and cisplatin-induced emesis but not that induced by copper sulphate. AM404 reduced only emesis induced by cisplatin without affecting other parameters measured. Following intracerebral administration only olvanil antagonised cisplatin-induced emesis, but this was associated with transient hypothermia. In conclusion, olvanil demonstrated clear anti-emetic activity in the absence of overt cardiovascular, homeostatic, or behavioural effects associated with the pungent vanilloid, RTX. Our studies indicate that non-pungent vanilloids may have a useful spectrum of anti-emetic properties via central and/or peripheral mechanisms after peripheral administration. © 2009 Elsevier Ltd. All rights reserved.

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