Receptor Multiplicity By Christian George Over the past three decades the diversity and selectivity of ligands has increased and it has become clear and evident that multiple subtypes of receptors exist. That is subtypes within many previously defined classes of receptors. Due to the advances in scientific research especially over the past decade with molecular cloning, there has been a revelation in the presence of several closely related subtypes of receptors where only a single species was thought to exist, and some receptor subtypes have been shown to be differentially expressed during development, differentially regulate physiological systems, regulate transmitter release, be involved in permanent changes in the brain via integration. Knowledge of receptor subtypes is of interest to the researcher, at present many studies are being carried out into the investigation of new receptors and the mechanisms of known receptors. Manipulation of the receptors has now been achieved facilitating the search for new receptors. There is a huge diversity and receptor multiplicity involving subtypes and a few examples are going to be discussed in this essay involving some history and identification of subtypes, various imaging of subtypes, and some of the more detailed roles that they play in our physiological systems with pharmacological experimental evidence to support this.The term “receptor multiplicity” was mentioned above from carrying out research there is no general definition of “receptor multiplicity”, however there are examples which display “receptor multiplicity”. The Opioid receptors have been subtyped, and there is evidence for the existence of receptor multiplicity. The evidence is supported by the fact that high affinity 1 receptors not only bind morphine but enkephalins as well, in addition to 2 receptors that preferentially bind morphine. This demonstrates that rec...
