The alpha-1A adrenergic receptor (ñ<sub>1A</sub> adrenoreceptor), also known as ADRA1A, formerly known also as the alpha-1C adrenergic receptor, is an alpha-1 adrenergic receptor, and also denotes the human gene encoding it. There is no longer a subtype ñ<sub>1C</sub> receptor. At one time, there was a subtype known as ñ<sub>1C</sub>, but it was found to be identical to the previously discovered ñ<sub>1A</sub> receptor subtype. To avoid confusion, the naming convention was continued with the letter D.
There are 3 alpha-1 adrenergic receptor subtypes: alpha-1A, -1B and -1D, all of which signal through the Gq/11 family of G-proteins. Different subtypes show different patterns of activation. The majority of alpha-1 receptors are directed toward the function of epinephrine, a hormone that has to do with the fight-or-flight response.
This gene encodes the alpha-1A-adrenergic receptor. Alternative splicing of this gene generates four transcript variants, which encode four different isoforms with distinct C-termini but having similar ligand binding properties.
ñ1A-adrenergic receptor subtypes increase inhibition at dendrodendritic synapses, suggesting a synaptic mechanism for noradrenergic modulation of olfactory driven behaviors.