Meperidine opioid receptor binding

Although morphine and meperidine are quite similar in their clinical effects, they are not that similar in chemical composition. The important chemical determinant of an opioid analgesic, however, is not its structural resemblance to morphine, but its ability to bind with and activate an opioid receptor. 

Mechanism of action Meperidine binds to opioid receptors, particularly k receptors. 

Fig. 24.14. A representation of the enkephalin binding site of p opioid receptors (85). (A) An enkephalin bound to the receptor. (B) Morphine binding the receptor by utilizing the T-subsite (i.e., the tyrosine-binding site). (C) A meperidine-type opioid binding the receptor by utilizing the P-subsite (i.e., the phenylalanine-binding site).

Opioid drugs and peptides that bind to the opioid receptors produce the primary general and specific clinical effects summarized in Table 8.1. The opioids relevant to this review are those that are used in medicine today meaiung, therefore, the frequently administered analgesics, particularly morphine, codeine, and synthetic analogs such as fentanyl, meperidine, and methadone. 

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