The effectiveness of Hering's nerve stimulation in controlling penicillin-induced seizures in the rat is dependent on the amygdala.
OBJECTIVE
This study tests the hypothesis that the ability of Hering's nerve stimulation (HNS) to blunt seizure activity is dependent on the availability of dopamine in the amygdala.


METHODS
In 10 rats, Hering's nerve (HN) on the right side was isolated and placed on an electrode and penicillin was locally placed on each rat's left frontoparietal region to induce seizures. After the initiation of seizures, HN was stimulated. After the recurrence of seizure activity, the left basolateral amygdala was injected with 1.0 microl of normal saline, dopamine, haloperidol or 1% lidocaine in sequential tests. HN was stimulated after each injection and the latency and amplitude of the seizure activity were assessed.


RESULTS
Focal cortical penicillin induced seizures that resulted in tonic-clonic movement of the limbs and face that lasted 35-45 min. Tonic-clonic movements of the limbs and face of similar latency and amplitude were induced by repeated reapplication of penicillin in untreated rats. HNS decreased seizure activity, but infusion of haloperidol or lidocaine into the basolateral amygdala blocked this antiseizure effect of HNS. In contrast, infusion of saline or dopamine had no effect on the ability of HNS to blunt seizure activity. None of the amygdala injections altered the latency or amplitude of seizure activity.


CONCLUSIONS
These results demonstrate that the ability of HNS to blunt seizure activity in the rat is dependent on an intact dopamine system in the basolateral amygdala. These data will hopefully be useful in furthering our understanding of the circuitry that allows peripheral nerve stimulation to alter seizure activity.
Tubbs
R Shane
RS
Department of Cell Biology, University of Alabama at Birmingham, USA. richard.tubbs@ccc.uab.edu
Wellons
John C
JC
Patwardhan
Ravish V
RV
Oakes
W Jerry
WJ
Wyss
J Michael
JM
D000679:Amygdala / Q000187:drug effects / Q000503:physiopathology*; D000818:Animals; D002316:Cardiotonic Agents / Q000627:therapeutic use*; D002346:Carotid Sinus / Q000187:drug effects / Q000294:innervation* / Q000503:physiopathology*; D004195:Disease Models, Animal; D004298:Dopamine / Q000627:therapeutic use*; D004558:Electric Stimulation; D005930:Glossopharyngeal Nerve / Q000187:drug effects / Q000503:physiopathology*; D008297:Male; D010406:Penicillins / Q000009:adverse effects*; D051381:Rats; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012640:Seizures / Q000139:chemically induced* / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors
D002316:Cardiotonic Agents; D010406:Penicillins; D004298:Dopamine