The Descending Control Mechanism Activates Once Noxious Stimuli

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The descending control mechanism activates once noxious stimuli reaches the higher level processing area of the brain. Inhibition can occur through opiate release Descending Pathways The descending pathways involved in pain utilise efferent motor nerves (gamma motor neurons). These pathways are involved in analgesic response or motor response to pain. pain modulation with brain areas(Tracey & Mantyh, 2007) pain modulation with brain areas(Gebhart, 2004) areas work together through inhibition or facilitation of nociceptive signals. Monoamines such as; serotonin, norepinephrine, or dopamine mediate modulation in the DH by binding to their according receptor subtypes of the afferent nociceptive fibres (Millan, 2005; Zhao et al., 2007; Pertovaara, 2006) periaqueductal gray (PAG)- motor, sensory and autonomic response. Located in the midbrain. Once activated by the spinomesencephalic tract, it releases a pentapeptide known as enkephalin, an endogenous ligand that binds to the delta opioid receptors in the body. A low level of analgesia is produced (Varga, et al, 2004; Carrive, 1993). Initiates inhibitory response to noxious stimuli by activating the rostral ventromedial medulla (RVM) (Fields, 2006) the second section of the PAG-RVM-DH inhibitory pathway. The RVM projects bilaterally to the DH via the dorsolateral funiculi and ventromedial funiculi (Porreca, Ossipov & Gebhart, 2002). There are two populations of neurons, on-cells and off-cells, that have been identified in

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