We again used our innovative research approach to study gut-microbiota-brain interface at individual synapse (splanchnic nerve fibers innervating the adrenal medulla, a simple model of catecholaminergic neurotransmission) during exposure to metabolic stress (insulin-induced hypoglycemia detected in the hypothalamus) (Giri et al., 2019; LaGamma et al., 2021). The gene discussed is INS; the disease is Hypoglycemia.