Collagen melt-down

with morphine together with subanalgesic doses of a second opiate did not develop tolerance to the morphine even after seven days of treatment. Although morphine is a favored choice for easing pain, a major drawback of its long-term use is the development of tolerance, which results in reduced analgesic effects upon long-term use. Morphine binds the opioid receptor (MOR), one member of the large G protein–coupled receptor family. Once bound by natural ligands such as endorphins, or several opiate drugs such as methadone, opioid receptors normally undergo desensitization via DAMGO helps morphine-bound receptors (white) enter the cell. W hi st le r/ El se vi er