Effects of adrenalectomy and hypophysectomy on postictal seizure protection

Endogenous opioid systems activated by seizures appear to contribute to the postictal inhibition of subsequent seizure activity. In consideration of the possible postictal anticonvulsant actions of endogenous opioids of peripheral origin, we examined whether intact adrenal or pituitary sources of these opioids are necessary for the progressive decline in convulsion intensity and duration normally recorded during a series of 6 intermittent maximal electroshocks (MES). Adrenalectomy did not alter the progressive seizure protection associated with repeated MES. Hypophysectomy, in contrast, increased convulsion duration and abolished progressive reductions in convulsion severity. These data indicate that: adrenal secretions do not substantially contribute to postictal protective mechanisms, and endogenous opioids of pituitary origin may be involved in postictal protective mechanisms.