During a systemic inflammatory response, the effect of non-steroidal anti-inflammatory drugs on seizure susceptibility in the immature brain may depend on the proconvulsant and anticonvulsant mechanisms simultaneously induced by the elevation of parenchymal prostaglandin E2 levels

Abstract

Clinical evidence from paediatric neurology supports the possibility that a protracted inflammatory state in the central nervous system (CNS) may enhance the predisposition of brain tissue to develop seizures. Consequently, non-steroidal anti-inflammatory drugs (NSAIDs) as well as selective cyclooxygenase-2 (COX-2) inhibitors were expected to positively modulate seizure susceptibility during a systemic inflammatory response. Nevertheless, experimental findings and clinical evidence provide controversial results. As a possible explanation for these apparent discrepancies, it is hypothesised that the amount of prostaglandin E₂ (PGE₂) induced in the immature brain parenchyma during systemic inflammatory response is crucial since PGE₂ plays a dual role. Indeed, on the one hand, this prostaglandin increases seizure susceptibility by stimulation of glutamate release from neurons and astrocytes. On the other hand, however, the same prostaglandin induces a massive release of corticosterone, being this hormone known to inhibit efficiently the seizure susceptibility of the immature brain. Hence, the dose–response curve of any given NSAID/COX-2 inhibitor on seizure susceptibility is expected to show different patterns, depending on the amount of PGE₂ levels produced in the brain parenchyma during the effect of drug. The proposed hypothesis also suggests that mild to moderate increase of PGE₂ levels in the immature brain parenchyma may act as a ‘preconditioning’ stimulus, i.e., it may confer a transient resistance to develop seizure-induced brain injury, besides to efficiently counteract seizure susceptibility.