Effects of various nonopioid receptor antagonists on the antinociceptive activity of Muntingia calabura extracts in mice.
This study was carried out in mice to determine the nonopioid receptor signaling pathway(s) that might modulate the antinociceptive activity of the aqueous and chloroform extracts of Muntingia calabura (M. calabura) leaves, using the hot-plate test. The leaves of M. calabura were sequentially soaked [1:2 (w/v); 72 h] in distilled water (dH(2)O) and chloroform. The 50% concentration extracts were selected for this study based on the plant's previously established antinociceptive profiles. The mice (n = 7) were pretreated (s.c.) for 10 min with the selected nonopioid receptor antagonists, followed by the (s.c.) administration of the respective extract. The latency of discomfort was recorded at the interval time of 0.5, 1, 2, 3, 4 and 5 h after the extract administration. The 5 mg/kg atropine, 10 mg/kg phenoxybenzamine, 10 mg/kg yohimbine, 10 mg/kg pindolol, 1 mg/kg haloperidol and 10 mg/kg bicuculline caused significant (p < 0.05) reduction in the aqueous extract-induced antinociceptive activity. The 10 mg/kg phenoxybenzamine, 10 mg/kg yohimbine, 10 mg/kg pindolol and 10 mg/kg bicuculline caused significant (p < 0.05) reduction in the chloroform extract-induced antinociceptive activity. In conclusion, the central antinociceptive activity of M. calabura leaves appears to be involved in the modulation of various nonopioid receptor signaling pathways. Its aqueous extract antinociceptive activity is mediated via modulation of the muscarinic, alpha(1)-adrenergic, alpha(2)-adrenergic, beta-adrenergic, dopaminergic and GABAergic receptors, while its chloroform extract activity is mediated via modulation of the alpha(1)-adrenergic, alpha(2)-adrenergic, beta-adrenergic and GABAergic receptors.
Faculty of Pharmacy, Science and Technology Complex, Universiti Teknologi MARA, Selangor, Malaysia. shaza8174@yahoo.com
Z A
ZA
Zakaria
M H
MH
Hassan
M N H
MN
Nurul Aqmar
M
M
Abd Ghani
S N H
SN
Mohd Zaid
M R
MR
Sulaiman
G
G
Hanan Kumar
C A
CA
Fatimah
D000818:Animals; D045467:Elaeocarpaceae / Q000737:chemistry*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010146:Pain / Q000188:drug therapy*; D010147:Pain Measurement; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects / Q000378:metabolism; D018341:Receptors, Adrenergic, alpha-2 / Q000187:drug effects / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism; D011954:Receptors, Dopamine / Q000187:drug effects / Q000378:metabolism; D018079:Receptors, GABA / Q000187:drug effects / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
D010936:Plant Extracts; D018340:Receptors, Adrenergic, alpha-1; D018341:Receptors, Adrenergic, alpha-2; D011943:Receptors, Adrenergic, beta; D011954:Receptors, Dopamine; D018079:Receptors, GABA; D011976:Receptors, Muscarinic