The distribution pattern of M2 and Adrenergic α2 receptors on inferior colliculi in male newborns of diabetic rats

Despite the high prevalence of diabetes in the world, its possible effects throughut pregnancy on neonatal auditory nervous system development are still unknown. In the present research, maternal diabetes’ impact on the M2 and Adrenergic α2 receptors expression in the inferior colliculus (IC) of male newborn rats was investigated. Female rats were grouped into three: sham, insulin-treated diabetic, and diabetic. Diabetes was induced through streptozotocin (STZ) injection as one dose intraperitoneally (65 mg/kg). After mating and delivery, male rats were euthanized on P0, P7, and P14. Immunohistochemistry (IHC) was used to study the distribution pattern of receptors. The present study indicated that the expression of M2 receptors in the diabetic group was significantly increased in pairwise comparisons in the sham and diabetic treated with insulin groups (P < 0.001, each). The highest M2 expression was for the diabetic group on P14 and the lowest one was for the sham group on P0. The Adrenergic α2a receptors expression in the diabetic group was significantly reduced in pairwise comparisons in the sham and diabetic treated with insulin groups (P < 0.001, each). The highest Adrenergic α2a expression was for the sham group on P14 and the lowest one was for the diabetic group on P0. There was no significant difference between the sham and insulin groups regarding all receptors expression. This study demonstrated a time-dependent significant decrease in Adrenergic α2a but a time-dependent significant increase in M2 receptors expression.