The effects of arginine-8 vasopressin on blood vessels supplying the cerebral cortex.
A videocamera and a dissecting microscope have been used to record the effects of arginine-8 vasopressin (AVP) upon pial blood vessels in anaesthetised rats. Topical application of AVP caused a contraction of pial arteries, but had no measureable effect upon the diameter of veins. The smallest concentration of AVP that was effective in contracting arteries was 10(-7) mU/microliter. Stronger solutions (10(-5) to 2.0 mU/microliter) produced approximately the same (45%) reduction of external diameter. Contraction was maximal 0.25-1.0 min after application of the hormone, had almost recovered (10% contraction) after 10 min, and showed complete recovery by 30 min. Concentrations of AVP that were greater than 10(-3) mU/microliter produced tachyphylaxis, so that a second application of AVP 30 min later had considerably less effect. Concentrations less than 10(-3) mU/microliter produced no detectable tachyphylaxis. These results suggest that blood flow to the normal cerebral cortex may be partly under tonic control by the local concentration of AVP.
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002536:Cerebral Arteries / Q000187:drug effects*; D002540:Cerebral Cortex / Q000098:blood supply*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013618:Tachyphylaxis / Q000187:drug effects
D001127:Arginine Vasopressin