Introduction/Overview Serotonin (5-hydroxytryptamine, 5‑HT) is a pivotal modulator of vascular tone, platelet aggregation, gastrointestinal motility, and central nervous system (CNS) neurotransmission. Autacoids that mimic or block serotonin’s actions—serotonin agonists and antagonists—play crucial roles in therapeutic and diagnostic settings. Their clinical relevance spans management of migraine, irritable bowel syndrome, pulmonary hypertension, and acute coronary syndromes, among…

Introduction/Overview Histamine is a biogenic amine that functions as a key autacoid in the human body, mediating a wide array of physiological and pathological responses. It is released by mast cells, basophils, enterochromaffin‑like cells, and neurons, and exerts its effects through four G protein‑coupled receptor subtypes (H1, H2, H3, H4). The clinical relevance of histamine…

Introduction/Overview The autonomic nervous system (ANS) exerts considerable influence over skeletal muscle tone through reflex arcs and interregional signaling. Pharmacologic agents that modulate this control are commonly employed to alleviate spasticity, manage acute musculoskeletal pain, and facilitate surgical procedures. A thorough understanding of skeletal muscle relaxants is essential for clinicians and pharmacists, as these drugs…

Introduction/Overview Beta-adrenergic blockers, commonly referred to as beta blockers, constitute a pivotal class of agents within autonomic nervous system pharmacology. Their ability to antagonize β-adrenergic receptors underlies a broad spectrum of therapeutic applications, particularly in cardiovascular medicine. As the prevalence of hypertension, heart failure, arrhythmias, and ischemic heart disease continues to rise, the relevance of…

Introduction / Overview Alpha-adrenergic blockers constitute a pivotal class of pharmacotherapeutic agents that modulate sympathetic nervous system activity by antagonizing α-adrenergic receptors. Their principal clinical applications encompass hypertension, benign prostatic hyperplasia (BPH), and certain vasospastic disorders. The therapeutic potential of these agents is rooted in their ability to inhibit vasoconstriction, lower peripheral resistance, and relieve…

Introduction/Overview Sympathomimetics and adrenergic agonists constitute a diverse group of pharmacologic agents that emulate the actions of endogenous catecholamines, predominantly norepinephrine and epinephrine. These compounds are pivotal in the regulation of cardiovascular, respiratory, and metabolic processes, and their therapeutic utility spans acute and chronic conditions. The autonomic nervous system (ANS) exerts a profound influence on…

Introduction/Overview Adrenergic transmission constitutes a central component of the autonomic nervous system (ANS), mediating rapid adjustments to cardiovascular, metabolic, and respiratory functions. Catecholamines—primarily norepinephrine and epinephrine—serve as primary neurotransmitters and hormones, respectively, engaging a spectrum of α‑ and β‑adrenergic receptors distributed throughout the body. A detailed understanding of the biochemistry, receptor pharmacology, and therapeutic manipulation…