Disruption of cerebellar cholinergic system in hypoxic neonatal rats and its regulation with glucose, oxygen and epinephrine resuscitations

Abstract

Cholinergic system is important for respiratory control from the first days of life. Disturbances in cholinergic pathway due to early life stress like hypoxic shock can adversely affect the ventilatory response. The present study evaluates neonatal hypoxic insult mediated cholinergic disturbances and the role of glucose, oxygen and epinephrine resuscitation. The changes in total muscarinic, muscarinic M1, M2, M3 receptors and the enzymes involved in acetylcholine metabolism – cholineacetyl transferase and acetylcholine easterase in the cerebellum were analyzed. Hypoxic stress decreased cerebellar muscarinic receptor density with a decreased muscarinic M1, M2 and M3 receptor gene expression. The metabolic shift in the acetylcholine synthesis and release is indicated by the decreased cholineacetyl transferase mRNA expression and increased acetylcholine esterase gene expression. Glucose, acting as a precursor for acetyl choline synthesis and an immediate energy source, helps in reversing the cholinergic disturbances in hypoxic neonates. The limitation of immediate oxygenation and epinephrine administration in ameliorating cholinergic disturbances in hypoxic neonates was also reported. This will help in devising a better resuscitation program for the management of neonatal hypoxia.