GABA opioids

GABA opioids, interleukin-1 (IL-1), and tumor necrosis factor a (TNFa) all inhibit REM sleep. 

Bossert JM, Franklin KB Pentobarbital-induced place preference in rats is blocked by GABA, dopamine, and opioid antagonists. Psychopharmacology (Bed) 157 115— 122, 2001... 

The mu, delta and kappa opioid receptors are coupled to G° and G proteins and the inhibitory actions of the opioids occur from the closing of calcium channels (in the case of the K receptor) and the opening of potassium channels (for /i, d and ORL-1). These actions result in either reductions in transmitter release or depression of neuronal excitability depending on the pre- or postsynaptic location of the receptors. Excitatory effects can also occur via indirect mechanisms such as disinhibition, which have been reported in the substantia gelatinosa and the hippocampus. Flere, the activation of opioid receptors on GABA neurons results in removal of GABA-mediated inhibition and so leads to facilitation. 

The reinforcing effects of opiate drugs involve a number of neuronal pathways [21]. In the VTA, opiates stimulate p-opioid receptors on GABA neurons that synapse on dopamine neurons. This inhibits the GABA neurons, leading to disinhibition of the dopamine neurons and enhanced dopamine release in the nucleus accumbens and other target areas (Fig. 56-3). Opiates also exert dopamine-independent effects in the nucleus accumbens by activating... 

The diagram below shows the pathway of pain transmission from the peripheral nerves to the cerebral cortex. There are three levels of neuronal involvement and the signals may be modulated at two points during their course to the cerebral cortex. Descending inhibitory pathways arise in the midbrain and pass to the dorsal horn as shown. Multiple different neurotransmitters are involved in the pathway and include gamma-aminobutyric acid (GABA), N-methyl-D-aspartate (NMDA), noradrenaline and opioids. 

Action duration of GABAa opening, leading to CP current Stimulates GABA inhibits NMDA Inhibits NMDA and opioid n receptors (stimulates k, and S) Stimulates GABA... 

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