Effect of phosphocreatine on reflex activity of the brain stem reticular formation

The effects of phosphocreatine (PCr) on startle reflexes, known to be relayed through the brain stem reticular formation (RF), were investigated on chloralose-anesthetized rats. PCr (10^–6 to 10^–3 M) was either applied superficially to the bottom of the fourth ventricle or microinjected into the reticular gigantocellular nucleus. The PCr effect was found to depend on its concentration. At low concentrations (10^–6 to 10^–5 M), PCr markedly facilitated the reflexes; sometimes its application gave rise to additional, later and longer, discharges following startle reflexes, whereas an inhibitory effect predominated at higher PCr concentration (10^–4 to 10^–3 M). Possible mechanisms of PCr action on the studied reflexes are discussed.Neirofiziologiya/Neurophysiology, Vol. 25, No. 3, pp. 272–278, 1993.