The influence of Bay K 8644 treatment on (+/-)-epibatidine-induced analgesia

Brain Res. 1995 Apr 24;678(1-2):244-50. doi: 10.1016/0006-8993(95)00189-w.

Abstract

The purpose of this investigation was to determine if analogous to (-)-nicotine's analgesic effect, the analgesic effect of the recently characterized potent nicotinic acetylcholine receptor (nAChR) agonist (+/-)-epibatidine was altered in response to treatment with the calcium channel agonist (+/-)-Bay K 8644. In addition, the effects of the enantiomers, (+)-Bay K 8644, reported to be a calcium channel antagonist, and (-)-Bay K 8644, reported to be a calcium channel agonist were examined. (+/-)-Bay K 8644 (2.8 mumol/kg; i.p.) produced a large analgesic response in mice in the hot-plate paradigm that rapidly dissipated by 30 min after treatment. This analgesic effect of (+/-)-Bay K 8644 was not prevented by pre-treatment with the nicotinic antagonist mecamylamine (5 mumol/kg; i.p.). Treatment with non-analgesic doses of the calcium channel agonists (+/-)- and (-)-Bay K 8644 (1.4 mumol/kg; i.p.) significantly potentiated the analgesic effect of (+/-)-epibatidine (0.05 mumol/kg; i.p.). Potentiation of (+/-)-epibatidine's analgesic effect occurred when the agonists were administered prior to (+/-)-epibatidine or after (+/-)-epibatidine as long as analgesia testing was conducted 15 to 30 min after Bay K 8644 treatment. Pre-treatment with the calcium channel antagonist (+)-Bay K 8644 was found to attenuate (+/-)-epibatidine-induced analgesia. When given after (+/-)-epibatidine, (+)-Bay K 8644 had no effect on (+/-)-epibatidine's analgesic effect. These data provide additional in vivo evidence that altering calcium dynamics can modulate neuronal nAChR function.

MeSH terms

  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / pharmacology*
  • Analgesia*
  • Animals
  • Bridged Bicyclo Compounds / pharmacology
  • Bridged Bicyclo Compounds, Heterocyclic*
  • Calcium Channels / drug effects
  • Male
  • Mecamylamine / pharmacology
  • Mice
  • Mice, Inbred Strains
  • Nicotinic Agonists / pharmacology
  • Pyridines / pharmacology
  • Time Factors

Substances

  • Bridged Bicyclo Compounds
  • Bridged Bicyclo Compounds, Heterocyclic
  • Calcium Channels
  • Nicotinic Agonists
  • Pyridines
  • Mecamylamine
  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
  • epibatidine