Power point is about alpha 1 receptor which is a G-coupled receptor and it's mechanism. How it is different from Alpha 2 receptor.

1. Alpha-1 adrenergic receptor
Sabah Mansoor
2014-PhD-1070

2. Alpha-1 adrenergic receptor
• alpha-1 (α1) adrenergic receptor is a G protein Coupled
Receptor (GPCR) associated with the Gq, heterotrimeric
protein.
• more responsive to Norepinephrine than to epinephrine.
• Catecholamines like norepinephrine (noradrenaline) and
epinephrine (adrenaline) signal through the α1-adrenergic
receptor in the central and peripheral nervous systems.

3. Types of alpha receptors
• α-adrenoceptors exist on peripheral sympathetic nerve
terminals and are divided into two subtypes α1, and α2.
• α1 is found mostly postsynaptically, whilst α2 although
typically sited presynaptically, can also occur
postsynaptically.
• Alpha 1 adrenergic receptor consists of three highly
homologous subtypes, including α1A, α1B, α1D- adrenergic.

5. α-Adrenoceptor Location and function
Alpha 1 receptors are located on:
• all vascular smooth muscle, although densities vary
throughout the body
• GI & urinary sphincters
• dilator muscle of the iris
• arrector pili muscle of hair follicles
• On central and peripheral nervous system

6. • In the Central Nervous System they are found mostly
postsynaptically and have an excitatory function.
• Peripherally they are responsible for contraction and are
situated on vascular and on non-vascular smooth muscle.
• α1-adrenoceptors on vascular smooth muscle are located
intrasynaptically and function in response to neurotransmitter
release.
• For non-vascular smooth muscle they can be found on the
liver, where they cause hepatic glycogenolysis and potassium
release. On the heart they mediate a positive inotropic effect.
• Cause relaxation of Gastro Intestinal smooth muscle and
decrease salivary secretion.

7. Signaling Cascade

9. agonists and antigonists
Alpha 1 agonists
vasoconstrictive agents they are used to reduce edema and
inflammation. naphazoline, phenylephrine and
propylhexedrine.
Alpha 1 antagonists
causes vasodilation and decreased peripheral resistance;
therefore they are used in the treatment of hypertension
(prazosin). Treatment of benign prostatic hyperplasia.
tamsulosin is a subtype-selective alpha 1A receptor that has
more specificity toward smooth muscle in genitourinary
tract.

11. REFERENCES
• Stedeford T, Cardozo-PF, Vultaggio B, Muro CC, Luzardo GE, Harbison
RD. 2001. Alpha1-andrenergic receptors and their significance to
chemical-induced nephrotoxicity—a brief review. Res. Commun. Mol.
Pathol. Pharmacol. 110 (1-2): 59-72.
• Chen ZJ, Minneman KP. 2005. Recent progress in alpha 1-andrenergic
receptor research. Acta Pharmacol Sin. 26 (11): 1281-7.
• Piascik MT, Perez DM. 2001. Alpha1-angrenergic receptors: new
insights and directions. J. Pharmacol. Exp. Ther. 298 (2): 403-10.
• Sushmita P,Peter BR. 2011. The functional role of the alpha-1
andrenergic receptors in cerebral blood flow regulation. Indian J.
Pharmacol. 43 (5): 502-506.