Regional brain 3H-digitoxigenin and monoamine content during the development of convulsions produced by system digitoxigenin.

The uptake of 3H-digitoxigenin (3H-DIGT), administered by intravenous infusion to conscious, unrestrained rats, increased with time in the medulla-pons, cerebellum, cerebral cortex, corpus striatum, hippocampus, hypothalamus, and midbrain coincident with the development of behavioral and motor disruption. At four minutes of infusion, during clonic convulsions, uptake appeared to follow reported differences in regional blood flow, ranging from 0.48 microgram/gm (hypothalamus) to 0.67 microgram/gm (cerebellum). After 5 1/2 minutes of infusion, rats still in clonic convulsions had no further increase in uptake; rats entering tonic convulsions had two- to three-fold increases in 3H-DIGT uptake, ranging from 1.00 microgram/gm (hypothalamus) to 1.65 microgram/gm (cerebellum). Electroshock-induced tonic convusions at 2 minutes of infusion increased 3H-DIGT uptake two- to three-fold in all regions, suggesting that the increased neuronal activity associated with the tonic convulsion enhanced the uptake of 3H-DIGT into all regions. The only significant monamine alteration was a slightly decreased medulla-pons serotonin level after 5 1/2 minutes of infusion.