Transfer between atropine-induced spiking in the perirhinal cortex and electrical kindling of the amygdala

We have recently determined that microinfusions of atropine sulphate into the perirhinal cortex (PRC) of adult Sprague-Dawley rats result in the dose dependent generation of epileptiform spike activity. Several observations suggested that atropine-induced spiking (AIS) and amygdaloid kindled seizures may share common neuronal mechanisms: (a) PRC atropine infusions occasionally resulted in the development of generalised seizures resembling those produced by amygdaloid kindling and which were accompanied by simultaneous discharge recorded from the PRC and amygdala, and (b) concurrent low amplitude spiking was occasionally recorded from the amygdala during non-seizure inducing infusions. Using kindling transfer, the present study sought to determine whether AIS possesses some epileptogenic characteristics which are common to an electrically generated afterdischarge. Repeated PRC infusions of atropine sulphate supra-threshold for the elicitation of spiking appeared to produce a positive transfer in that significantly more advanced behavioural seizures were elicited during initial amygdaloid kindling. These findings suggest that AIS (and/or atropine-induced behavioural seizures) and amygdala-kindled seizures share, at some level, common neuronal mechanisms.