Depression of the cat cortical visual evoked potential by soman.
The effects of intravenous administration of the anticholinesterase agent soman (pinacolyl methylphosphonofluoridate, 3-15 micrograms/kg) on the visual evoked potential (VEP) were examined in cats using phase-reversed sine wave grating stimuli of different spatial frequencies and contrasts. Doses of 5-7 micrograms/kg caused a depression of the VEP across all spatial frequencies in an abrupt, non-graded fashion. Studies in which contrast was varied showed that VEP depression resulted primarily from a decrease in the system gain rather than a change in the contrast sensitivity, and that response depression increased with increasing contrast. The dominant changes in gain revealed by these studies are consistent with a modulation of potassium conductance in the cell membrane which previous studies have shown to be dependent on a cholinergic mechanism.
DeBruyn
E J
EJ
Department of Electrical Engineering, Vanderbilt University, Nashville, TN 37235.
Corbett
G K
GK
Bonds
A B
AB
D000818:Animals; D002415:Cats; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D002802:Cholinesterases / Q000097:blood; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D005074:Evoked Potentials, Visual / Q000187:drug effects*; D007275:Injections, Intravenous; D012999:Soman / Q000008:administration & dosage / Q000494:pharmacology*; D013037:Spatial Behavior; D014793:Visual Cortex / Q000187:drug effects / Q000502:physiology
D002800:Cholinesterase Inhibitors; D012999:Soman; D002802:Cholinesterases