AUTHOR=Afify Elham A. , Alkreathy Huda M. , Ali Ahmed S. , Alfaifi Hassan A. , Khan Lateef M. 

TITLE=Characterization of the Antinociceptive Mechanisms of Khat Extract (Catha edulis) in Mice

JOURNAL=Frontiers in Neurology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2017.00069

DOI=10.3389/fneur.2017.00069

ISSN=1664-2295

ABSTRACT=<p>This study investigated the antinociceptive mechanisms of khat extract (100, 200, and 400 mg/kg, i.p.) in four pain models: two thermic (hot plate, tail-flick) and two chemical (acetic acid, formalin) models. Male mice were pretreated intraperitoneally (i.p.) with the opioid receptor blocker naloxone (5 mg/kg), the cholinergic antagonist atropine (2 mg/kg), the selective α<sub>1</sub> blocker prazosin (1 mg/kg), the dopamine D<sub>2</sub> antagonist haloperidol (1.5 mg/kg), or the GABA<sub>A</sub> receptor antagonist, bicuculline (1 mg/kg) 15 minutes prior to i.p. injection of khat extract (400 mg/kg). Khat extract reduced the nociceptive response of mice in the four pain tests. Naloxone significantly inhibited the antinociceptive effect of khat extract in the hot plate, tail-flick, and the first phase of formalin tests. Bicuculline significantly antagonized the antinociceptive effect of khat extract on the hot plate and tail-flick tests. Haloperidol significantly reversed the antinociceptive effect of khat extract on the tail-flick test and the first phase of formalin test. These results provide strong evidence that the antinociceptive activity of khat extract is mediated <italic>via</italic> opioidergic, GABAergic, and dopaminergic pathways. The mechanism of the antinociceptive action of khat may be linked to the different types of pain generated in animal models.</p>