Bh. Ali et al., CENTRAL-NERVOUS-SYSTEM ACTIVITY OF RHAZYA-STRICTA (DECNE) IN MICE, Clinical and experimental pharmacology and physiology, 22(4), 1995, pp. 248-253
1. The effects of orally administered aqueous lyophilized extract of t
he leaves of Rhazya stricta (2, 4 and 8 g/kg) on aspects of nervous sy
stem function were investigated in mice. 2. In three antinociceptive t
ests (hot plate, abdominal constriction, and warm water tail nick test
s), the extract exhibited dose-dependent and significant antinocicepti
ve activity. Naloxone was ineffective in antagonizing the analgesic ef
fect of Rhazya stricta on tail-nick and abdominal constriction tests,
possibly indicating that this effect occurs via non-opiate pathways. 3
. Pretreatment of mice with the xenobiotic metabolizing enzymes inhibi
tor cimetidine (50 mg/kg) did not significantly alter the antinocicept
ive action of the extract, indicating that the effect is probably due
to the parent compound(s) present in the extract and not to metabolite
s thereof. 4. Rhazya stricta produced dose-dependent sedation, decreas
ed motor activity, and impaired motor control. Time spent on a rotarod
treadmill was significantly decreased after treatment with the extrac
t. 5. Rhazya stricta extract (8 g/kg) produced a degree oi sedation co
mparable to that produced by diazepam (5-10 mg/kg), and also significa
ntly increased the reaction time of the tail-flick test, an action whi
ch was not produced by diazepam. 6. Administration of R. stricta extra
ct potentiated pentobarbitone sleeping time in a dose dependent manner
. The extract did not significantly antagonize picrotoxin induced conv
ulsions. The extract (4 and 8 g/kg) significantly decreased the rectal
temperature of normothermic and hyperthermic mice. 7. Pretreatment wi
th R. stricta extract (8 g/kg) completely prevented the occurrence of
aggressive behaviour in male mice. 8. It is concluded that the crude e
xtract of R. stricta has central nervous system depressant properties.