Changes in plasma catecholamine levels following injection of prostaglandin F2alpha into the basal cistern in rabbits.

We measured plasma epinephrine and norepinephrine concentrations in a rabbit model simulating subarachnoid hemorrhage (SAH), following the injection of prostaglandin F(2alpha) (PGF(2alpha)) into the basal cistern. In this model, plasma epinephrine values increased significantly (to 4.2-fold those before injection), substantially more than norepinephrine (which increased 1.3-fold) at 5 minutes (min) after PGF(2alpha) injection. Dissection of autonomic outflow from the cervical spinal cord or ligation of the suprarenal veins reduced the changes in plasma catecholamine concentrations associated with PGF(2alpha) injection. These results suggest that the sympathetic discharge seen after PGF(2alpha) injection into the basal cistern in rabbits occurred through the sympatho-adrenal pathways.