Descending Inhibitory Pathway

Descending Inhibitory Pathway Desensitised State Desensitization Desmoplakin... 

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. 

P at the sensory neuron terminals in the spinal cord. It is also released in areas of the midbrain and medulla where it enhances the descending inhibitory pathways, which terminate in the spinal cord. 

Descending Inhibitory Pathway from the Midbrain and Brainstem... 

The locus cemleus is important for the regulation of attentional states and autonomic nervous system activity. It has also been implicated in the autonomic and stress-like effects of opiate withdrawal. A noradrenergic pathway originating from the locus cemleus which descends into the spinal cord is part of the descending inhibitory control system, which has an inhibitory effect on nociceptive transmission in the dorsal horn. 

Siqueira-Lima, P. S., Araujo, A. A. S., Lucchese, A. M., Quintans, J. S. S., Menezes, P. R, Barreto, P. A., deLuccaJunior, W., Santos, M. R. V., Bonjardim, L. R., and Quintans-Junior, L. J. (2014). P-cyclodextrin complex containing Lippia grata leaf essential oil reduces orofacial nociception in mice-evidence of possible involvement of descending inhibitory pain modulation pathway. Basic and Clinical Pharmacology and Toxicology, 114(2), 188-196. 

At the same time it promotes a discharge of epinephrine from the adrenal medulla, as well as discharge of catecholamines from sympathetic nerve endings, resulting in activation of spinal cord and brain descending inhibitory pain pathways. 

The inhibitory spiny GABAergic neurons send projections by two major pathways whose net effect appears to exert balanced regulatory influences on the ascending thalamo- cortical circuits that mediate control of voluntary movement through the descending corticospinal projections to the spinal ventral-horn motoneurons that innervate skeletal muscles. A widely accepted, but tentative model of the basic anatomical connections of this complex is summarized schematically in Fig. 12.1(12,15,17-20). 

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