[The effect of a calcium channel blockade on the reactivity of the cerebral vessels in rabbits].
The changes of cerebrovascular reactivity (CVR) under influence of calcium antagonist nimodipine (0.01 and 0.06 mg/kg i.v.) and verapamil (0.6 and 1.0 mg/kg i.v.) were investigated in chronic experiments in 12 rabbits. Platinum electrodes were implanted into cortex, thalamus and hypothalamus, and cerebral blood flow was measured in these zones by H2-clearance method. CVR was evaluated as a ratio: cerebral blood flow after 7% CO2 inhalation to initial level. This ratio, or reactivity coefficient (RC), in normal conditions is 1.49-1.59. Nimodipine in dose 0.01 mg/kg resulted in significant decrease (by 15-20%) of RC only in cortex. In dose 0.06 mg/kg this decreased RC was about 20-30% in cortex and in hypothalamus, but in thalamus the changes of RC were insignificant. Verapamil in dose 0.6 mg/kg resulted in different changes of RC: increase in cortex, decrease in thalamus, but in hypothalamus no changes. In dose 1.0 mg/kg RC was decreased in cortex by 15-20%, in other zones were no changes.
Polevik
I V
IV
Karadzhaeva
G B
GB
Vaĭnshteĭn
G B
GB
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology; D002536:Cerebral Arteries / Q000187:drug effects* / Q000502:physiology; D002540:Cerebral Cortex / Q000098:blood supply; D004305:Dose-Response Relationship, Drug; D004567:Electrodes, Implanted; D007031:Hypothalamus / Q000098:blood supply; D009553:Nimodipine / Q000494:pharmacology; D011817:Rabbits; D013788:Thalamus / Q000098:blood supply; D013997:Time Factors; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D009553:Nimodipine; D014700:Verapamil
Vliianie blokady kal'tsievykh kanalov na reaktivnost' sosudov golovnogo mozga krolikov.