The alpha (α)-2 adrenergic receptor (or α2 adrenoceptor) is an adrenaline/noradrenaline receptor (with a significant preference for adrenaline) that is expressed in various parts of the body from the smooth muscle, blood vessels, to the insulin-secreting cells of the pancreas, digestive tract and various components of the CNS. In the brain stem it inhibits the release of noradrenaline and adrenaline in the sympathetic nervous system, in the prefrontal cortex it controls attention and impulse control (which it affects without serving as an autoreceptor/heteroreceptor there), the locus ceruleus where it inhibits noradrenaline and adrenaline production in the CNS, spinal cord, thalamus, hippocampus, cerebral cortex, midbrain, amygdala, cerebellum, hypothalamus, etc. It serves as an autoreceptor and heteroreceptor to noradrenaline, dopamine and acetylcholine.
Agonists frequently produce constipation, dry mouth, drowsiness, analgesia, dizziness, headache, depression, anxiety, fatigue, nausea, weight loss, sleep disturbances, vivid dreams, sexual dysfunction, urinary retention or incontinence and reduced blood pressure. They also alleviate withdrawal symptoms from a number of drugs of abuse (including alcohol, nicotine, opioids, etc.) and improve ADHD symptoms.
Antagonists produce sympathomimetic effects (e.g., increased blood pressure, increased alertness[note 1], increased heart rate, etc.), alleviate depression/anxiety/psychosis, etc.
- Noradrenergic and specific serotonergic antidepressants like mianserin, mirtazapine and setiptiline
- Antipsychotics, especially atypical antipsychotics like asenapine, clozapine, olanzapine, paliperidone and zotepine.
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- The TRIP database provides clinical publications about evidence-based medicine.
- ↑ It is worth noting, however, that most antagonists have additional antihistamine effects that counteract these effects
- ↑ Brunton, LL; Chabner, BA; Knollmann, BC, ed. (2010). Goodman & Gilman's Pharmacological Basis of Therapeutics (12th ed.). New York, USA: McGraw-Hill Professional. ISBN 978-0-07-162442-8.
- ↑ 2.0 2.1 Rang, HP; Dale, MM; Ritter, JM; Flower, RJ; Henderson, G (2012). "Noradrenergic transmission". Rang and Dale's Pharmacology (7th ed. ed.). New York: Elsevier. ISBN 978-1-4377-1933-8.
- ↑ Saunders, C; Limbird, LE (November 1999). "Localization and trafficking of alpha2-adrenergic receptor subtypes in cells and tissues.". Pharmacology & Therapeutics 84 (2): 193–205. PMID 10596906. doi:10.1016/S0163-7258(99)00032-7.