The activation of bulbo-spinal controls by peripheral nociceptive inputs: diffuse noxious inhibitory controls.

作者：Luis Villanueva, Daniel Le Bars · 发表于：PubMed · 年份：1995 · 被引用次数：255 · 研究领域：Pain Management and Placebo Effect

Some neurones in the dorsal horn of the spinal cord are strongly inhibited when a nociceptive stimulus is applied to any part of the body, distinct from their excitatory receptive fields. This phenomenon was termed "Diffuse Noxious Inhibitory Controls" (DNIC). DNIC influence only convergent neurones, and these inhibitions can be triggered only by conditioning stimuli which are nociceptive. The inhibitions are extremely potent, affect all the activities of the convergent neurones and persist after the removal of the conditioning stimulus. Only activity of A delta- or A delta- and C- peripheral fibres can trigger DNIC. DNIC are sustained by a complex loop which involves supraspinal structures since, unlike segmental inhibitions, they are not observed in animals in which the cord has previously been transected at the cervical level. The ascending and descending limbs of this loop travel respectively through the ventro-lateral and dorso-lateral funiculi, respectively. We proposed that DNIC result from the physiological activation of some brain structures putatively involved in descending inhibition. However, lesions of the mesencephalon, including the periaqueductal grey (PAG) and the rostral ventromedial medulla (RVM), including nucleus raphé magnus, did not modify DNIC. By contrast, lesions of subnucleus reticularis dorsalis (SRD) in the caudal medulla strongly reduced DNIC. Both electrophysiological and anatomical data support the involvement of SRD neurones in spino-bulbo-spi...