title: Analgesic properties of aqueous leaf extract of Haematostaphis barteri: involvement of ATP-sensitive potassium channels, adrenergic, opioidergic, muscarinic, adenosinergic and serotoninergic pathways.
abstract: BACKGROUND
  Pain is the most common cause of patients seeking medical advice as a result of its association with different pathologies. This study evaluated the antinociceptive property of Haematostaphis barteri as well as the possible mechanism(s) associated with its antinociceptive property.
  
  
  METHODS
  Mice were administered H. barteri (30-300 mg kg-1; p.o.), followed by intraplantar injection of 10 μL of 5% formalin into the hind paws. The pain score was determined for 1 h in the formalin test. The possible nociceptive pathways involved in the antinociceptive action of H. barteri were determined by pre-treating mice with theophylline (5 mg kg-1, a non-selective adenosine receptor antagonist), naloxone (2 mg kg-1, a non-selective opioid receptor antagonist), glibenclamide (8 mg kg-1; an ATP-sensitive K+ channel inhibitor), and atropine (3 mg kg-1; non-selective muscarinic antagonist).
  
  
  RESULTS
  H. barteri (30-300 mg kg-1) significantly and dose dependently precluded both first and second phases of nociception. Pre-treatment with naloxone had no effect on the analgesic activities of H. barteri in the first phase. Again, pre-treatment with atropine and glibenclamide did not significantly reverse the neurogenic antinociception of the extract in phase 1. However, theophylline reversed the analgesic effect of the extract in the first phase. In phase 2, theophylline had no effect on the analgesic activities of the extract. Naloxone, atropine, and glibenclamide significantly blocked the antinociception of H. barteri in the inflammatory phase of the formalin test.
  
  
  CONCLUSIONS
  H. barteri possesses antinociceptive property mediated via the opioidergic, adrenergic, muscarinic, ATP-sensitive K+ channels, and adenosinergic nociceptive pathways.
authors.forename: Elvis Ofori
authors.initials: EO
authors.lastname: Ameyaw
authors.forename: Kennedy Kwami Edem
authors.identifier: http://orcid.org/0000-0003-2948-9615
authors.initials: KK
authors.lastname: Kukuia
authors.forename: Ama Kyerea
authors.initials: AK
authors.lastname: Thomford
authors.forename: Samuel
authors.initials: S
authors.lastname: Kyei
authors.forename: Priscilla Kolibea
authors.initials: PK
authors.lastname: Mante
authors.forename: Johnson Nyarko
authors.initials: JN
authors.lastname: Boampong
mesh_terms: D059331:Adrenergic Neurons / Q000187:drug effects / Q000502:physiology; D027926:Anacardiaceae; D000700:Analgesics / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D005260:Female; D054086:KATP Channels / Q000037:antagonists & inhibitors* / Q000502:physiology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010147:Pain Measurement / Q000187:drug effects* / Q000379:methods; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves; D011976:Receptors, Muscarinic / Q000502:physiology; D011957:Receptors, Opioid / Q000502:physiology; D018047:Receptors, Purinergic P1 / Q000502:physiology; D059326:Serotonergic Neurons / Q000187:drug effects / Q000502:physiology
chemical_list: D000700:Analgesics; D054086:KATP Channels; D010936:Plant Extracts; D011976:Receptors, Muscarinic; D011957:Receptors, Opioid; D018047:Receptors, Purinergic P1