Alpha-1A Adrenergic Receptor (ADRA1A)

The alpha-1A adrenergic receptor (α1A adrenoreceptor), encoded by the ADRA1A gene, is a G protein-coupled receptor primarily coupled to Gq/11 proteins. Activation by agonists like norepinephrine and epinephrine leads to increased intracellular calcium levels and activation of protein kinase C pathways. It plays crucial roles in vasoconstriction, smooth muscle contraction, synaptic plasticity in the CNS via astrocyte-neuron interactions, and cardiac hypertrophy signaling. Antagonists like tamsulosin and silodosin are used to treat benign prostatic hyperplasia by relaxing smooth muscle in the prostate and bladder neck. Dysregulation of ADRA1A can contribute to hypertension and lower urinary tract symptoms. Recent research explores its broader roles in synaptic plasticity and cognition via glia-neuron communication pathways.

Other names

Alpha‑adrenergic receptor subtype AAlpha-1C adrenergic receptor (historical)ADRA1A receptor

Agonists (norepinephrine, epinephrine) bind to ADRA1A, activating Gq/11 proteins, which then activate phospholipase C (PLC). PLC catalyzes the production of inositol trisphosphate (IP3) and diacylglycerol (DAG) from phosphatidylinositol bisphosphate (PIP2). IP3 increases intracellular calcium levels, and DAG activates protein kinase C. Antagonists (tamsulosin, silodosin) competitively bind to ADRA1A, preventing agonist binding and reducing smooth muscle contraction.