Morphine (MOP)

Morphine can inhibit the pain area of cerebral cortex and has strong analgesic effect. It has an inhibitory effect on the respiratory center and cough center, and an excitatory effect on the smooth muscles of the biliary tract, ureter, bronchus, etc., increasing their tension.The anatomy of rats injected intraperitoneally with morphine revealed that morphine was distributed in the heart, liver, spleen, kidney, adrenal gland, stomach, small intestine, islets of Langerhans, submandibular gland, sublingual gland and brain tissue. Of course, the time of morphine appearance varied in various parts. The distribution of morphine in the body is affected by the dose and route of administration. HPLC was used to study acute and chronic morphine exposed rats. It was found that the concentration of morphine in myocardium and blood of acute morphine exposed rats was significantly higher than that in brain tissue, while the concentration of morphine in myocardium, blood and brain tissue of chronic morphine exposed rats was basically the same. It was confirmed that the dose and duration of administration had an effect on the distribution of morphine in rats. Morphine has a strong physiological dependence. Its toxic mechanism is due to the compensatory adaptation of morphine acting as opioid receptors in different brain regions, activating the second messenger system and the changes of gene transcription and translation, causing the changes of Da, opioid peptides, GABA neural pathways in the brain, and keeping the opioid receptors in an excited state for a long time