Chemical control of cerebral circulation. Modification by a new vasodilator (YC-93).
This study was undertaken to investigate influences of a new vasodilator, YC-93, a derivative of 1,4-dihydropyridine, on cerebral circulation and cerebrovascular CO2 reactivity. Cerebrocortical PO2, cerebrocortical PCO2, cerebrocortical blood flow and arterial blood pressure were continuously recorded by means of a PO2 electrode, a PCO2 electrode and a plate-type crossed thermocouple flowmeter placed on an exposed pial surface of the cat brain. The changes in each parameter induced by YC-93 were compared with those induced by papaverine hydrochloride. The effects of 5% CO2 inhalation were compared before and after the intravenous injection of YC-93. YC-93 (0.01 mg/kg) showed a more marked and longer-lasting hypotensive effect that papaverine (1 mg/kg) and yet produced a significant increase in cerebrocortical PO2. After the administration of YC-93, the degree of the increase in cerebrocortical PO2 during 5% CO2 inhalation was reduced significantly in comparison with that before the administration. The above data indicates that YC-93 has a vasodilating effect on cerebral blood vessels and that the drug causes a decrease in cerebrovascular CO2 reactivity.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001923:Brain Chemistry / Q000187:drug effects; D002245:Carbon Dioxide / Q000032:analysis; D002415:Cats; D002540:Cerebral Cortex / Q000098:blood supply*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D009578:Nitrobenzenes / Q000494:pharmacology; D010100:Oxygen / Q000032:analysis; D010208:Papaverine / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology*; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology*
D009578:Nitrobenzenes; D011725:Pyridines; D014665:Vasodilator Agents; D002245:Carbon Dioxide; D010208:Papaverine; D010100:Oxygen