Spinal mediation of the increases in arterial pressure and heart rate in response to intrathecal administration of bicuculline

The present experiments were designed to determine the mechanisms by which the intrathecal administration of the GABAA antagonist, bicuculline (2.2 and 8.8 nmol), at the second thoracic spinal segment (T2) affects cardiovascular function in the anaesthetized rat. Bicuculline produced a dose-related, transient increase in arterial pressure and heart rate which peaked at 5-7 min and persisted for 30 min or more, depending on dose. There was a …