α1-Adrenergic Receptors play an important role in the physiological response to epinephrine and norepinephrine, particularly in the cardiovascular system. All three cloned α1 receptors (α1A, α1B, and α1D) couple to Gq/11. While their cellular distribution is clear, their functional role is less so due to the lack of specific agonists/antagonists.As these receptors lack specific agonists/antagonists knock-out mice studies have most significantly shed light on the cellular role of Adrenoceptors. Individual α1-Adrenoceptor knock-out mice do not display physical abnormalities in general. Similar knock-out studies indicate that all α1 subtypes seem to be involved in the regulation of blood pressure3. Also, studies indicate that α1D-Adrenoceptor seems to play an important role in aortic contraction4, renal function, nociception, basal locomotor activity3 as well as bladder contraction.
