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Endogenous morphine modulates acute thermonociception in mice
Author(s) -
Guarna M.,
Bianchi E.,
Bartolini A.,
Ghelardini C.,
Galeotti N.,
Bracci L.,
Neri C.,
Sonetti D.,
Stefano G.
Publication year - 2002
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.0022-3042.2001.00708.x
Subject(s) - endogeny , morphine , nociception , hot plate test , damgo , neurotransmitter , chemistry , central nervous system , endocrinology , pharmacology , agonist , endogenous opioid , medicine , receptor , opioid , opioid receptor
The endogenous synthesis of morphine has been clearly demonstrated throughout the phylogenesis of the nervous system of mammals and lower animals. Endogenous morphine, serving as either a neurotransmitter or neurohormone, has been demonstrated in the nervous system of both verteb‐rates and invertebrates. As one of the effects of exogenous morphine is the modulation of pain perception, we investigated the effects that the depletion of endogenous morphine had on nociceptive transmission. The immunoneutralization of endogenous morphine from brain extracellular spaces was obtained through the intracerebroventricular administration of affinity purified anti‐morphine IgG to mice, which then underwent the hot plate test. Endogenous morphine immunoneutralization decreased thermal response latency and attenuated the anti‐nociceptive effect of the mu selective agonist DAMGO in hot plate test suggesting that endogenous morphine is involved in pain modulation.