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A lateralized deficit in morphine antinociception after unilateral inactivation of the central amygdala.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Manning, Barton H. |
| Copyright Year | 1998 |
| Abstract | The amygdala is a forebrain region that is receiving increasing attention as a modulator of pain sensation. The amygdala contributes to antinociception elicited by both psychological factors (e.g., fear) and exogenous opioid agonists. Unlike the midbrain periaqueductal gray matter (PAG) or rostral ventromedial medulla, the amygdala is a pain-modulating region that has clear bilateral representation in the brain, making it possible to determine whether pain-modulating effects of this region are lateralized with respect to the peripheral origin of noxious stimulation. Unilateral inactivation of the central nucleus of the amygdala (Ce) plus adjacent portions of the basolateral amygdaloid complex (with either the excitotoxin NMDA or the GABAA agonist muscimol) reduced the ability of morphine to suppress prolonged, formalin-induced pain derived from the hindpaw ipsilateral, but not contralateral, to the inactivated region. This effect was evident regardless of the nociceptive scoring method used (weighted scores or flinch-frequency method) and was not accompanied by a concurrent reduction in morphine-induced hyperlocomotion. Unilateral lesions restricted to the basolateral amygdaloid complex (i.e., not including the Ce) did not reduce the ability of morphine to suppress formalin-induced pain derived from either hindpaw. The results constitute the first report of a lateralized deficit in opioid antinociception after unilateral inactivation of a specific brain area and show the first clear neuroanatomical dissociation between antinociceptive and motor effects of systemically administered morphine in the rat. The amygdala appears to modulate nociceptive signals entering the ipsilateral spinal dorsal horn, probably through monosynaptic connections with ipsilateral portions of the PAG. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.jneurosci.org/content/jneuro/18/22/9453.full.pdf |
| PubMed reference number | 9801383v1 |
| Volume Number | 18 |
| Issue Number | 22 |
| Journal | The Journal of neuroscience : the official journal of the Society for Neuroscience |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Amygdaloid structure Attention deficit hyperactivity disorder Cell Nucleus Central gray substance of midbrain Cerebellar Nuclei Excitotoxins Formalin Gray Matter Midbrain structure Modulator Device Component Morphine Movement Disorders Muscimol N-Methylaspartate Pain Perception Prosencephalon Score Structure of posterior gray horn of spinal cord central amygdalar nucleus |
| Content Type | Text |
| Resource Type | Article |
