Somatostatin causes vasoconstriction, reduces blood flow and increases vascular permeability in the rat central nervous system.

摘要: Using radiolabeled microspheres, spinal cord blood flow was measured after subarachnoid injections of 3.1- to 12.5-nmol doses somatostatin through either indwelling i.t. catheters or acutely inserted intervertebral needles. With injection technique, caused significant dose-dependent reductions in thoracic and lumbosacral that could be partially blocked by a 5-min preinjection the receptor antagonist cyclo[7-aminoheptanoyl-Phe-D-Trp-Lys-Thr(Bzl)], which has previously been shown block hindlimb flaccidity produced these conscious rats. The duration changes were appreciably less rats injected catheters. Somatostatin-induced perfusion accompanied transient pressor responses, reduced cardiac output, 3-fold increases cerebrospinal fluid lactic acid concentrations breakdown blood-spinal barrier, as reflected significantly increased extravasation [125I]bovine serum albumin. By 24 hr postinjection, dose appreciable cellular injury, evidenced elevations lactate dehydrogenase. After topical application exposed pial vessels parietal cortex, comparable immediate intense dose-related arteriolar vasospasm subsequent visible macromolecular tracer Evans blue dye. We conclude vasoconstrictory effects on brain rat must recognized appreciated when studying its neuropharmacological actions vivo.