title: Peripheral neurobiologic mechanisms of antiallodynic effect of warm water immersion therapy on persistent inflammatory pain.
abstract: Water immersion is widely used in physiotherapy and might relieve pain, probably by activating several distinct somatosensory modalities, including tactile, pressure, and thermal sensations. However, the endogenous mechanisms behind this effect remain poorly understood. This study examined whether warm water immersion therapy (WWIT) produces an antiallodynic effect in a model of localized inflammation and whether peripheral opioid, cannabinoid, and adenosine receptors are involved in this effect. Mice were injected with complete Freund's adjuvant (CFA; intraplantar; i.pl.). The withdrawal frequency to mechanical stimuli (von Frey test) was used to determine 1) the effect of WWIT against CFA-induced allodynia and 2) the effect of i.pl. preadministration of naloxone (a nonselective opioid receptor antagonist; 5 µg/paw), caffeine (a nonselective adenosine receptor antagonist; 150 nmol/paw), 1,3-dipropyl-8-cyclopentylxanthine (DPCPX; a selective adenosine A1 receptor antagonist; 10 nmol/paw), and AM630 (a selective cannabinoid receptor type 2 antagonist; 4 µg/paw) on the antiallodynic effect of WWIT against CFA-induced allodynia. Moreover, the influence of WWIT on paw inflammatory edema was measured with a digital micrometer. WWIT produced a significant time-dependent reduction of paw inflammatory allodynia but did not influence paw edema induced by CFA. Naloxone, caffeine, DPCPX, and AM630 injected in the right, but not in the left, hind paw significantly reversed the antiallodynic effect of WWIT. This is the first study to demonstrate the involvement of peripheral receptors in the antiallodynic effect of WWIT in a murine model of persistent inflammatory pain.
authors: Laboratório de Neurociência Experimental (LaNEx), Universidade do Sul de Santa Catarina, Campus Grande Florianópolis-Palhoça, SC, Brazil; Programa de Pós-Graduação em Ciências da Saúde (PPGCS), Universidade do Sul de Santa Catarina, Campus Grande Florianópolis-Palhoça, SC, Brazil; Curso de Fisioterapia, Universidade do Sul de Santa Catarina, Campus Grande Florianópolis-Palhoça, SC, Brazil.
authors: Daniel F
authors: DF
authors: Martins
authors: Rômulo N
authors: RN
authors: Brito
authors: Juliana
authors: J
authors: Stramosk
authors: Ana P
authors: AP
authors: Batisti
authors: Fernanda
authors: F
authors: Madeira
authors: Bruna L
authors: BL
authors: Turnes
authors: Leidiane
authors: L
authors: Mazzardo-Martins
authors: Adair R S
authors: AR
authors: Santos
authors: Anna P
authors: AP
authors: Piovezan
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D048588:Benzoxazines / Q000494:pharmacology; D004195:Disease Models, Animal; D004487:Edema / Q000209:etiology / Q000628:therapy; D005620:Freund's Adjuvant / Q000633:toxicity; D006930:Hyperalgesia / Q000209:etiology* / Q000628:therapy*; D007101:Immersion; D007211:Indoles / Q000494:pharmacology; D007249:Inflammation / Q000150:complications*; D008297:Male; D051379:Mice; D009025:Morpholines / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009281:Naphthalenes / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009446:Neurobiology; D010147:Pain Measurement; D043682:Receptor, Adenosine A1; D043885:Receptor, Cannabinoid, CB2 / Q000378:metabolism; D011957:Receptors, Opioid / Q000378:metabolism; D018508:Water Purification
chemical_list: D048588:Benzoxazines; D007211:Indoles; D009025:Morpholines; D009281:Naphthalenes; D009292:Narcotic Antagonists; D043682:Receptor, Adenosine A1; D043885:Receptor, Cannabinoid, CB2; D011957:Receptors, Opioid; C027513:N(6)-cyclohexyladenosine; D009270:Naloxone; C070417:(3R)-((2,3-dihydro-5-methyl-3-((4-morpholinyl)methyl)pyrrolo-(1,2,3-de)-1,4-benzoxazin-6-yl)(1-naphthalenyl))methanone; D005620:Freund's Adjuvant; D000241:Adenosine; C094023:iodopravadoline
keywords: adenosine; analgesia; cannabinoid; chronic pain; opioid; water therapy