Influence of ketanserin on 5-hydroxytryptamine-induced cerebrovascular spasm in the cat.
In an experimental cat model the leptomeningeal vasculature was studied by a vital microscopic brain window technique. The brain window was connected to a thermostat-regulated pool of Elliot's solution. By air-drying (10 min) of the arachnoid mesothelium access for drugs, applied into the pool, was established to the adventitia of the leptomeningeal vasculature. Application of 5-hydroxytryptamine (5-HT) (10(-6)-10(-4) M) caused dose-dependent contractile responses (morphometry of outer vessel diameter) of both arteries and veins of three different sizes (large, 200-300 microns; medium, 50-150 microns; small, 30-50 microns). A well-reproducible contractile response was obtained at challenge with 5-HT (10(-4) M) from the various vascular beds with most pronounced effects on the arterial side. If the animals were pretreated with peripheral blockade of serotonergic (5-HT2) receptors (ketanserin 0.3 mg/kg i.v.), challenge with 5-HT (10(-4) M) elicited no significant vascular responses on either the arterial or venous sides. Vital microscopy further visualized capillary beds after ketanserin pretreatment that were not seen under control conditions.
Vällfors
B
B
Dahlström
A
A
Boström
S
S
Ahlman
H
H
D000818:Animals; D002415:Cats; D002560:Cerebrovascular Circulation / Q000187:drug effects; D002546:Ischemic Attack, Transient / Q000473:pathology / Q000503:physiopathology*; D007650:Ketanserin; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology*; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology*
D010880:Piperidines; D012702:Serotonin Antagonists; D012701:Serotonin; D007650:Ketanserin