Morphine Tolerance Effects on Neurotransmitters and Related Receptors: Definition, Overview and Update

Abstract

Morphine is the essential opioid drug that use in the clinic to attenuate chronic and severe pain. However long-term administration of morphine leads to the development of anti-nociceptive morphine tolerance. Mechanisms that involved in morphine tolerance are complicated and affect a different part of CNS and change neural circuits. One of the most critical candidates for the development of morphine tolerance are neurotransmitters Which makes the communication between neurons and establish neural circuits. The most prominent neurotransmitters that involved in the development of morphine tolerance are NMDA one of the most popular excitatory neurotransmitter, GABA most important inhibitory neurotransmitter in CNS, and monoaminergic neurotransmitters: dopamine, noradrenaline, adrenaline and serotonin have a lot of crucial roles in CNS. Also, Changes that occur in the level of opioid receptors, neurotransmitters and its receptors make alternation cross-talk between neurons. Understanding these changes help us to have an overall concept about the development of morphine tolerance.

Assessment of Probiotics Mixture on Memory Function, Inflammation Markers, and Oxidative Stress in an Alzheimer's Disease Model of Rats

“…Fifty male Wistar rats (200-250 g) were used in this study. Each animal was housed in one cage and had free access to food and water [24] . Rats were randomly divided into five groups (n = 10 per group): (1) control group, without any intervention and injection; (2) sham group, with PBS intrahippocampal injection without any dietary plan; (3) Alzheimer group, with Aβ1-40 intrahippocampal injection without any dietary plan; (4) Alzheimer-probiotics (A + P) group, with Aβ1-40 intrahippocampal injection and receiving 2 g (10 10 CFU) probiotics (Lactobacillus reuteri, Lactobacillus rhamnosus, and Bifidobacterium infantis) orally once a day for 10 weeks; (5) AD + rivastigmine group, receiving rivastigmine (0.6 mg/kg) orally once a day for two weeks.…”

Effect on Neurotransmitters in Alcoholic People

“…[30]. The human body works like a perfect machine, and the introduction of a foreign object like alcohol causes the harmony of the machinery to bend out of place and throw everything out of balance [31].The article gives as to how our brain acts in the presence of alcohol, not even for a long time but short as well, and is helpful to find a corrective methodic treatment for alcoholism [32][33][34][35][36][37].…”

Repeated Administration of Baclofen Modulates TRPV-1 Channel Expression by PKC Pathway in Dorsal Root Ganglia of Spinal Cord in Morphine Tolerance Model of Rats

“…Opioids are the most common analgesic drugs applied in clinical practice to treat chronic pain [ 1 ] . As a MOR agonist, morphine is used extensively to attenuate chronic pain, but morphine tolerance, dependence, and addiction restrict its administration [ 2 , 3 ] . Nowadays, co-administration of morphine plus other drugs suggests diminishing this tolerance [ 4 - 6 ] .…”

“…As a GABA B agonist, baclofen might be beneficial to minimize morphine tolerance [ 7 , 8 ] . Recently, behavioral and molecular studies have shown that baclofen could be used along with opioid drugs to delay tolerance and dependence to opioids [ 3 , 9 ] . Evidence has also indicated that baclofen may potentiate morphine analgesia in chronic use of opioids and can reduce many adverse effect of chronic administration of opioids [ 6 , 10 ] .…”