Effects of Suxamethonium on the Cerebrum Following Disruption of the Blood-Brain Barrier in Dogs

Abstract

We have studied the effects of suxamethonium 1.0 mg kg-1 i.v. on cerebral blood flow (CBF), cerebral metabolic rate (CMRO2), and the electroencephalogram (EEG) in dogs anaesthetized with halothane (1.0 MAC) following blood-brain barrier (BBB) disruption with intracarotid (i.c.) mannitol. The combination produced a transient increase in CBF, while CMRO2 did not change. These responses were similar to those produced by i.c. mannitol plus i.v. saline. Suxamethonium produced desynchronization of the EEG that persisted longer than that produced by saline. In only one of the six animals was the desynchronization sustained (90 min) beyond that found in dogs with a normal BBB. We conclude that disruption of the BBB did not enhance the cerebral stimulating effects of i.v. suxamethonium, and did not increase the likelihood of seizure activity following suxamethonium.

Porcine Model for Studying the Passage of Non-Depolarizing Neuromuscular Blockers Through the Blood-Brain Barrier

“…In spite of this, several neuromuscular blocking drugs have been shown to produce, not only EEG evidence of arousal reactions, but also decreases in frequency and amplitude in animals with disrupted BBB, which may indicate a depressant effect on the activating system of the medulla oblongata [1]. Therefore, interest has been focused on the passage of neuromuscular blockers through the supposedly compromised BBB and their possible toxic effects on cholinergic pathways in brainstem and midbrain structures [2]. If neuromuscular blocking agents do enter the CNS in large concentrations, recovery in patients with altered states of BBB might be delayed because of anticholinergic effects in midbrain structures (e.g.…”