PNS. Neurohumoral transmission, co-transmission. Neurotransmitters and their receptors, including non-adrenergic and non-cholinergic (NANC)

The peripheral nervous system (PNS) plays a vital role in connecting the central nervous system with different organs, tissues, muscles, and glands of the body. A clear understanding of the organisation and functions of the PNS is essential for pharmacy students and aspirants preparing for competitive examinations such as GPAT, NIPER, UPSC Drug Inspector, AIIMS Pharmacist, Railway Pharmacist, SSC, ESIC, and State Pharmacist examinations. The PNS includes the somatic and autonomic nervous systems, which regulate voluntary and involuntary activities through complex neural pathways.

An important aspect of peripheral neuropharmacology is neurohumoral transmission, the process by which nerve impulses are converted into chemical signals through the release of neurotransmitters. Acetylcholine and noradrenaline are the major neurotransmitters involved in cholinergic and adrenergic transmission, respectively. Their synthesis, storage, release, receptor interaction, and termination of action form the basis for understanding the mechanism of many important drugs.

Modern concepts of neurotransmission have also established the importance of co-transmission, in which a single neuron may release more than one chemical messenger. In addition, several non-adrenergic and non-cholinergic (NANC) neurotransmitters, including nitric oxide, ATP, vasoactive intestinal peptide, substance P, and neuropeptide Y, play important roles in the regulation of smooth muscle activity, vascular tone, gastrointestinal function, pain transmission, and other physiological processes.

The following notes and multiple-choice questions provide an easy-to-understand and exam-oriented revision of the organisation and functions of the PNS, neurohumoral transmission, co-transmission, neurotransmitters, and their receptors. Important facts, receptor mechanisms, mnemonics, and challenging MCQs have been included to help students strengthen conceptual understanding and prepare effectively for pharmacy and healthcare competitive examinations.

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