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Single exercise stress reduces central neurotrophins levels and adenosine A 1 and A 2 receptors expression, but does not revert opioid‐induced hyperalgesia in rats
Author(s) -
Medeiros Liciane Fernandes,
Nunes Éllen Almeida,
Lopes Bettega Costa,
Souza Andressa,
Cappellari Angélica Regina,
Freitas Joice Soares,
Macedo Isabel Cristina,
Kuo Jonnsin,
Cioato Stefania Giotti,
Battastini Ana Maria de Oliveira,
Caumo Wolnei,
Torres Iraci L. S.
Publication year - 2020
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1002/jdn.10059
Subject(s) - hyperalgesia , medicine , endocrinology , (+) naloxone , morphine , adenosine , spinal cord , neurotrophin , acetylcholinesterase , opioid , receptor , anesthesia , chemistry , nociception , biochemistry , psychiatry , enzyme
Background This study assessed the effects of an acute stress model upon the long‐term hyperalgesia induced by repeated morphine administration in neonatal rats. We also evaluated neurotrophins and cytokines levels; expressions of adenosine and acetylcholine receptors, and acetylcholinesterase enzyme at the spinal cord. Material and methods Male Wistar rats were subjected to morphine or saline administration from P8 to P14. Thermal hyperalgesia and mechanical hyperesthesia were assessed using the hot plate (HP) and von Frey (vF) tests, respectively, at postnatal day P30 and P60. After baseline measurements, rats were subjected to a single exercise session, as an acute stress model, at P30 or P60. We measured the levels of BDNF and NGF, interleukin‐6, and IL‐10 in the cerebral cortex and the brainstem; and the expression levels of adenosine and muscarinic receptors, as well as acetylcholinesterase (AChE) enzyme at the spinal cord. Results A stress exercise session was not able to revert the morphine‐induced hyperalgesia. The morphine and exercise association in rats induced a decrease in the neurotrophins brainstem levels, and A 1 , A 2A , A 2B receptors expression in the spinal cord, and an increase in the IL‐6 cortical levels. The exercise reduced M2 receptors expression in the spinal cord of naive rats, while morphine prevented this effect. Conclusions Single session of exercise does not revert hyperalgesia induced by morphine in rats; however, morphine plus exercise modulate neurotrophins, IL‐6 central levels, and expression of adenosine receptors.