Opiate properties

Chang, K.J., and Cuatrecasas, P. Heterogeneity and properties of opiate receptors. Fed Proc 40 2729-2734, 1981. 

Research into the properties of opiates has provided more insights into the processes that make up psychopharmacological actions than any other class of drug this is because opiates bind to receptor sites that are affected by endorphins - the brain s indigenous opiates. These endorphins are implicated in pain thresholds, natural highs and our capacity for addiction to opiates. 

The pharmacological properties of the cloned opiate receptors are similar to the characteristics of the endogenously expressed receptors [9, 36, 45]. The binding of opiates to the cloned receptors is stereoselective and the antagonist naloxone interacts with all three of the cloned receptors, although naloxone had much lower af-... 

Changing the amino acid sequence of the cloned receptors by mutating nucleotides within the receptor cDNAs has proven to be an effective mechanism by which to identify structural features of the receptors responsible for their unique functional properties. In particular, site-directed mutagenesis has been employed to determine the ligand binding domains of each opiate receptor. 

Careful analyses of the pharmacologic properties of 3H-hailucinogen binding sites indicated that they may correspond to 5-HT receptors (in the case of 3H-LSD), sigma opiate receptors (in the case of 3H-PCP), or even GABA receptors (in the case of 3H-muscimol). Such data recall that hallucinogens should interfere markedly with the metabolism of neurotransmitters in the CNS. These hallucinogen-induced alterations of neurotransmitter metabolism and functions are summarized below. 

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