Abstract: Aim To observe the effects of galanin (Gal) antagonist M35 or M40 at different concentrations on the Gal-evoked outward-current in principal trigeminal nucleus (PrV) neurons.Methods The technique of whole-cell patch-clamp was used to record the change of membrane current.Results At doses of M35 0.01, 0.03 and 0.1 μmol·L^-1, the Gal-evoked outward- current decreased by 53.1%, 40.4% and 27.2%, respectively.While M35 1 and 3 μmol·L^-1, the current increased by 16.2% and 38.4%.At doses of M40 0.01 and 0.03 μmol·L^-1, the current increased by 93.7% and 68.4%, while for M40 0.3, 1 and 3μmol·L^-1, the current decreased by 49.2%, 69.9% and 87.2%, respectively.Conclusion M35 at low concentrations antagonizes the effect of Gal and at high concent rations acts as a Gal receptor agonist. Whereas M40 in high doses antagonizes the effect of Gal and in low doses exerts an autagonistic action. There may be different Gal subtype receptors in the same PrV neuron.

Key words: galanin, outw ard-current, principal trigeminal nucleus