ABSENCE OF EMETIC EFFECTS OF MORPHINE AND LOPERAMIDE IN SUNCUS-MURINUS

Citation
N. Selve et al., ABSENCE OF EMETIC EFFECTS OF MORPHINE AND LOPERAMIDE IN SUNCUS-MURINUS, European journal of pharmacology, 256(3), 1994, pp. 287-293
Citations number
31
Categorie Soggetti
Pharmacology & Pharmacy
ISSN journal
00142999
Volume
256
Issue
3
Year of publication
1994
Pages
287 - 293
Database
ISI
SICI code
0014-2999(1994)256:3<287:AOEEOM>2.0.ZU;2-Z
Abstract
The house musk shrew Suncus murinus recently has been introduced for t he study of emesis. We investigated the emetic effects of the opioids morphine (0.1-21.5 mg/kg i.p.) and loperamide (0.01-10 mg/kg i.p.) and found a complete lack of emetogenic potential. Nicotine, however, dos e dependently induced vomiting in the Suncus with an ED(50) of 8.8 mg/ kg s.c. and a 100% incidence at 20 mg/kg. This drug-induced vomiting w as reduced by morphine or loperamide: ED(50) values obtained were 1.2 mg/kg i.p. for morphine and 0.7 mg/kg i.p. for loperamide. Naloxone (2 mg/kg s.c.) antagonised the inhibitory effect of morphine (2 mg/kg i. p.) or loperamide (10 mg/kg i.p.). Serotonin (20 mg/kg s.c.) had less reliable emetogenic potency than nicotine in the Suncus with incidence s between 50 and 100%. However, the serotonin-induced vomiting was abo lished by morphine and loperamide and this inhibition was antagonised by naloxone. These results suggest that systemically administered opio ids are pure antiemetics in Suncus murinus in contrast to other animal models and man. Naloxone antagonism indicates that this antiemetic ef fect is mediated by opioid receptors.