ELECTRICAL KINDLING IS ASSOCIATED WITH INCREASES IN AMYGDALA ACETYLCHOLINE LEVELS - AN IN-VIVO MICRODIALYSIS STUDY

Using brain microdialysis, acetylcholine (Ach) levels were assessed in the nucleus amygdaloideus lateralis of electrically kindled rats usin g a cholinesterase inhibitor in the perfusion fluid to prevent Ach bre akdown. During kindling development, when the animals displayed afterd ischarges lasting more than 30 s but no seizures, a significant increa se in Ach levels (+66%) was observed after electrical stimulation. Ach levels were also elevated after a stage 5 kindled seizure (+48%), wit h no additional increment compared to rats experiencing only afterdisc harges. Chronic diazepam administration prevented kindling development and the increment in Ach overflow; however, diazepam itself(following acute administration) tended to decrease Ach levels in the amygdala. These findings are convergent with pharmacological data suggesting tha t changes in the cholinergic function may be important especially duri ng amygdaloid kindling development.