Pharmacological alterations after clot removal in monkey chronic cerebral vasospasm

An autologous blood clot was placed bilaterally around cerebral arteries in the basal subarachnoid space to mimic subarachnoid haemorrhage (SAH), Cynomolgus monkeys were randomised into five groups: sham operated group, clot removal group at 48, 72 or 96 h after SAH and clot group, The proximal parts of the middle cerebral arteries were cut into rings for isometric tension measurements at 7 days after SAH, Potassium chloride, 5-hydroxytryptamine (5-HT), norepinephrine (NE), adenosine triphosphate (ATP), prostaglandin F-2 alpha (PGF(2 alpha)) and haemoglobin all induced dose-dependent contractions, There was a progressive attenuation of the contractions in response to the agonists in the clot removal and the clot groups, which reached statistical significance at 48 h after SAH in the case of 5-HT and at 72 h in the cases of NE, ATP and PGF(2 alpha) as compared with the sham operated group, These pharmacological results suggest that clot removal should be within the first two days after SAH to prevent cerebral vasospasm. (C) Pearson Professional Ltd 1995