CBF response to L-dopa influenced by peripheral decarboxylase inhibitor and serotonin in conscious SHR-SP, SHR-SR and WK rats.
1. L-Dopa induced a 56% increase in frontal cortical blood flow (fcCBF) one hour after intraperitoneal administration in stroke-prone spontaneously hypertensive rats. The treatment with carbidopa did not alter the magnitude of the response but shortened the response time to half an hour. In stroke-resistant rats and in Wistar Kyoto rats, L-dopa decreased fcCBF. This response was reversed to different degree by carbidopa pretreatment. 2. Serotonin decreased fcCBF in all groups. L-Dopa administered one hour after serotonin resulted in a recovery to the control level in SHR-SR, an increase in fcCBF in WK but the decreased flow in SHR-SP was maintained till the end of the observation time. 3. The data suggest that the stroke-prone rats have an unusual response to L-dopa and that L-dopa and this combination with a peripheral decarboxylase inhibitor may have a beneficial effect on the improvement of cerebral blood flow especially when the pre-existing level of cerebral blood flow is reduced in severe hypertension.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002230:Carbidopa / Q000494:pharmacology*; D002262:Carboxy-Lyases / Q000037:antagonists & inhibitors; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D006859:Hydrogen / Q000378:metabolism; D006973:Hypertension / Q000503:physiopathology*; D007274:Injections, Intraperitoneal; D007980:Levodopa / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000502:physiology*
D012701:Serotonin; D007980:Levodopa; D006859:Hydrogen; D002262:Carboxy-Lyases; D002230:Carbidopa