To evaluate the influences of γ-aminobutyric acid (GABA) mechanisms on bladder hyperactivity after left middle cerebral artery occlusion, cystometric recordings were obtained from unanesthetized female rats. Intracerebroventricular administration of both muscimol (GABAA receptor agonist; 0.1–10 nmol) and baclofen (GABAB receptor agonist; 0.1–3 nmol) produced dose-dependent inhibitions of micturition with increases in bladder capacity (BC). The effects of high doses (1–10 nmol) were similar in sham-operated (SO) and cerebral-infarcted (CI) rats. However, lower doses of muscimol (0.1 or 0.3 nmol) and baclofen (0.1 nmol) reduced BC in CI rats. After bicuculline (GABAA receptor antagonist; 1 or 3 nmol) administration, BC in both SO and CI rats first decreased and subsequently increased. An increase in urethral pressure was observed after administration of bicuculline (3 nmol) but not with either muscimol or baclofen. Infarct volumes in muscimol-, bicuculline-, or baclofen-treated rats were not significantly different from those of vehicle-treated rats. These results suggest that GABAergic mechanisms inhibit the micturition reflex at the supraspinal level but that this can change as a result of CI.
EVALUATION OF THE ANTI-ISCHAEMIC EFFECT OF SELECTIVE COX-2 INHIBITOR (ROFECOXIB) IN PERMANENT LEFT MIDDLE CEREBRAL ARTERY OCCLUSION (FOCAL CEREBRAL ISCHEMIA MODEL) IN RATS
