AIM To observe the selective effects of
dihydrolycorine (DL) on isolated cerebral blood vessel of rabbit. MOTHEDS The
isolated basilar artery(BA) and thoracic aorta(TA) and
papillary muscles(PM) preparations were used to record change of tension induced by drugs. RESULTS Resting tension of BA was raised by DL and reduced by Nim. But both drugs had little effect in TA. DL produced a contraction dependent relaxation in noradrenaline (NA 100 μmol·L -1 ) or KCl (60 mmol·L -1 ) contracted BA and TA rings. The relaxative effect of DL was more potent in BA rings contracted by NA than that by KCl. The IC 50 values ware (6 69±3 12)×10 -4 and (3 41±1 52)×10 -3 mol·L -1 respectively. In the TA, DL inhibited contraction induced by NA,the IC 50 value was less than that in the BA. DL or Nim produced a concentration dependent inhibition of the contraction respones induced by electrical stimulation in PM. IC 50 value of DL inhibited contraction of the PM induced by electrical stimulation was significantly greater than that by NA in BA rings ( P< 0 01). CONCLUSION These data demonstrate that the DL had selected effects on BA. It may be related to antagonistic α 1 subtype and β receptor. The results suggest that DL may help in improving cerebral blood flow in cerebral ischemic area.