| Autoantibody Target | Abbreviation | Receptor Type | Functional Effect | Prevalence/Clinical Significance |
|---|---|---|---|---|
| Alpha-1 adrenergic receptor | α1-AR | GPCR | Impairs peripheral vasoconstriction; may contribute to venous pooling and orthostatic intolerance | ~89% of POTS patients in one cited study; widely implicated in autoimmune/hyperadrenergic POTS (pqac-00000010, pqac-00000042, pqac-00000043) |
| Beta-1 adrenergic receptor | β1-AR | GPCR | Enhances adrenergic cardiac responses; may promote tachycardia | Frequently elevated/reported in POTS autoantibody panels (pqac-00000009, pqac-00000010, pqac-00000013) |
| Beta-2 adrenergic receptor | β2-AR | GPCR | Enhances sympathetic outflow and abnormal adrenergic signaling | Frequently elevated; among the most common antibodies in post-COVID POTS series (pqac-00000010, pqac-00000036) |
| Muscarinic M2 acetylcholine receptor | M2AChR | GPCR | Impairs parasympathetic/cholinergic regulation of heart rate | Commonly found in autoimmune POTS literature and GPCR autoantibody profiles (pqac-00000010, pqac-00000013, pqac-00000036) |
| Muscarinic M3 acetylcholine receptor | M3AChR | GPCR | May affect smooth muscle and autonomic effector function | Reported in autonomic autoimmunity literature overlapping with POTS (pqac-00000010, pqac-00000013) |
| Angiotensin II type 1 receptor | AT1-R | GPCR | Alters vascular tone and RAAS signaling | Common in post-COVID POTS reports; often co-detected with β2-AR and M2R antibodies (pqac-00000010, pqac-00000036) |
| Ganglionic acetylcholine receptor | gAChR | Ligand-gated ion channel | Impairs autonomic ganglionic transmission | Recognized marker of autoimmune autonomic ganglionopathy; also reported in subsets of POTS patients (pqac-00000008, pqac-00000012, pqac-00000013) |
| Opioid-like 1 receptor | OLR1 / opioid-like 1 receptor | GPCR | May modulate autonomic signaling | Reported in expanded autoimmune POTS autoantibody profiles; clinical significance remains uncertain (pqac-00000013) |


*Table: This table summarizes the principal autoantibodies reported in POTS, the receptor classes they target, and their proposed physiologic effects. It is useful for understanding the autoimmune hypothesis of POTS and for distinguishing well-reported versus still-emerging antibody associations.*