Vip, short for vasoactive intestinal peptide, is a 28-amino-acid peptide belonging to a peptide family with members like glucagon, secretin, etc. It functions as a neurotransmitter, neuromodulator, and secretagog, regulating various physiological processes such as brain activity, neuroendocrine functions, cardiac activity, respiration, digestion, and sexual potency. It exerts its function via receptor-mediated systems, activating signal transduction pathways like cAMP [1].

Vip also plays roles in many other biological aspects. In rodent embryonic growth, extraembryonic-produced Vip may regulate early post-implantation development [2]. In the hippocampus, it controls GABAergic transmission and pyramidal cell activity, influencing synaptic plasticity and learning and memory processes [3]. In the CNS, Vip stimulates neuronal proliferation and differentiation during development, and in cancer cells, it promotes proliferation [4]. In allergic diseases, Vip secreted by neuronal and immune cells has immunological functions [5]. In asthma treatment, delivery systems carrying Vip show potential [6]. In the cortex, upper and deeper layer Vip + interneurons have transcriptional differences [7], and in the motor cortex, Vip interneurons have synapse-type-specific plasticity learning rules which may be harnessed to control epilepsy-related neuropathologies [8]. In the hypothalamic suprachiasmatic nucleus, Vip-neurons regulate blood glucose level through sympathetic activity enhancement [9].

In conclusion, Vip is crucial in multiple biological processes, from embryonic development to neural function, immune regulation, and glucose metabolism. Studies on Vip, especially through in vivo models, contribute to understanding its role in various disease areas such as epilepsy, allergic diseases, and metabolic disorders, providing potential directions for disease treatment and prevention.