What is an adrenaceptor?

Adrenaceptor can also be called an adrenergic receptor and is one of the proteins that spread along the membranes of presynaptic and postsynaptic neurons. The adrenoceptor serves as a recognition point for the binding of neurotransmitters Norepinephrine and epinephrine. There are two main classes of adrenoceptors. They are alpha- and beta-adreniceptors. The flow of ions across the cell membrane results in a change in potential or electricity in the membrane. This causes the release of a chemical or neurotransmitter from the presynaptic neuron into the synaptic cleft, a gap filled with liquid. When the neurotransmitter is released, it binds or joins the receptor points to the postsynaptic neuron that recognizes this particular neurotransmitter. Adrenaceptors are metabotropic receptors, which means, they drive ion channels.

In order to open and close the associated ion channels, and to flow through the adrenoceptor cell membrane, a number of metabolic steps must occur. This includesstimulation of g-proteins. When neurotransmitters bind to receptors, G-Proteins are activated and secondary messengers are generated. This results in activation of enzymes and opening and closing the associated ion channels. For this reason, the adrenaceptor is also called a receptor associated with G.

Adrenaceptors consist of two main groups: alpha-adrenergic receptors and beta-adrenergic receptors. These two groups were further divided into alpha _{1 -adrenergic receptors, alpha 2 -adrenergic receptors, beta 1 -Inrenergic receptors and beta -adrenergic receptors. These adrenaceptors bind to Norepinephrine and epinephrine neurotransmitters.}

alpha _{1 -adrenoceptors are found on the membrane of postsynaptic neurons. These adrenoceptors become active when norepinephrine binds to them, resulting in activation of secondary messengers and release of calcium.Calmodulin, binding protein, is bound to calcium, resulting in opening associated ion channels. This allows the ions to move through the cell membrane and neuron to become active. Alpha 2 -adrenoceptors are located on the presysynaptic neuron membrane and when activated by norepinephrine, reducing further release of the neurotransmitter, which makes the neuron inactive.}

Beta _{1 -IDRENEPTORS are located in the heart, and when the transmitters are stimulated, they lead to an increase in heart rate and cardiac contraction. Beta 2 -adrenoceptors are found in smooth muscles. When these adrenoceptors are activated, the smooth muscles in which they are located are released.}