TY - JOUR
T1 - Role of opioid receptors in the reduction of formalin-induced secondary allodynia and hyperalgesia in rats
AU - Ambriz-Tututi, Mónica
AU - Rocha-González, Héctor I.
AU - Castañeda-Corral, Gabriela
AU - Araiza-Saldaña, Claudia I.
AU - Caram-Salas, Nadia L.
AU - Cruz, Silvia L.
AU - Granados-Soto, Vinicio
N1 - Funding Information:
Authors greatly appreciate the technical and bibliographic assistance of Guadalupe C. Vidal-Cantú and Héctor Vázquez, respectively. Mónica Ambriz-Tututi, Héctor I. Rocha-González, Claudia I. Araiza-Saldaña, Nadia L. Caram-Salas and Gabriela Castañeda-Corral are Conacyt fellows. This work is part of the Ph.D. dissertation of Mónica Ambriz-Tututi and partially supported by Conacyt , grant 59879 to VGS.
PY - 2009/10/1
Y1 - 2009/10/1
N2 - This study assesses the effects of peripheral or intrathecal pre-treatment or post-treatment with μ, δ, κ and nociceptin/orphanin FQ (NOP) opioid receptor agonists (morphine, U-50488 [trans-(±)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]benzeneacetamide hydrochloride], DADLE [D-Ala2-Leu5-enkephalin] and nociceptin, respectively) on formalin-induced secondary mechanical allodynia and hyperalgesia in rats. 1% Formalin injection produced acute nociceptive behaviors (flinching and licking/lifting) followed by long-term tactile secondary allodynia and hyperalgesia. Neither peripheral (into the formalin-injected paw) nor intrathecal morphine post-treatment reversed formalin-induced secondary allodynia and hyperalgesia. In contrast, morphine pre-treatment prevented the development of these pain behaviors. Intrathecal and peripheral post- but not pre-treatment with U-50488 or DADLE significantly reduced secondary allodynia and hyperalgesia. Interestingly, nociceptin reduced both pain behaviors regardless of the administration site or treatment time. Local antinociceptive effects of morphine, DADLE, U-50488 or nociceptin were blocked by naltrexone, naltrindole, 5-guanidinonaltrindole and [Nphe1]nociceptin(1-13)NH2, respectively. These results suggest that the long-term nociceptive behaviors induced by formalin are differentially modulated by selective opioid receptor agonists. In addition, data suggest that peripheral and spinal δ and κ opioid receptors are important when nociceptive behaviors are established. In contrast, μ opioid receptors are more important at the beginning of the injury when the sensory system has not changed. NOP receptors participate diminishing both the development and maintenance of nociceptive behaviors. Results suggest that a barrage of afferent input induced by formalin injection initiates a long-term differential change in peripheral and spinal processing that affect the efficacy of opioid receptor agonists.
AB - This study assesses the effects of peripheral or intrathecal pre-treatment or post-treatment with μ, δ, κ and nociceptin/orphanin FQ (NOP) opioid receptor agonists (morphine, U-50488 [trans-(±)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]benzeneacetamide hydrochloride], DADLE [D-Ala2-Leu5-enkephalin] and nociceptin, respectively) on formalin-induced secondary mechanical allodynia and hyperalgesia in rats. 1% Formalin injection produced acute nociceptive behaviors (flinching and licking/lifting) followed by long-term tactile secondary allodynia and hyperalgesia. Neither peripheral (into the formalin-injected paw) nor intrathecal morphine post-treatment reversed formalin-induced secondary allodynia and hyperalgesia. In contrast, morphine pre-treatment prevented the development of these pain behaviors. Intrathecal and peripheral post- but not pre-treatment with U-50488 or DADLE significantly reduced secondary allodynia and hyperalgesia. Interestingly, nociceptin reduced both pain behaviors regardless of the administration site or treatment time. Local antinociceptive effects of morphine, DADLE, U-50488 or nociceptin were blocked by naltrexone, naltrindole, 5-guanidinonaltrindole and [Nphe1]nociceptin(1-13)NH2, respectively. These results suggest that the long-term nociceptive behaviors induced by formalin are differentially modulated by selective opioid receptor agonists. In addition, data suggest that peripheral and spinal δ and κ opioid receptors are important when nociceptive behaviors are established. In contrast, μ opioid receptors are more important at the beginning of the injury when the sensory system has not changed. NOP receptors participate diminishing both the development and maintenance of nociceptive behaviors. Results suggest that a barrage of afferent input induced by formalin injection initiates a long-term differential change in peripheral and spinal processing that affect the efficacy of opioid receptor agonists.
KW - Formalin test
KW - Neuroplasticity
KW - Opioid receptor
KW - Secondary allodynia
KW - Secondary hyperalgesia
UR - http://www.scopus.com/inward/record.url?scp=69749099589&partnerID=8YFLogxK
U2 - 10.1016/j.ejphar.2009.08.001
DO - 10.1016/j.ejphar.2009.08.001
M3 - Artículo
C2 - 19686723
SN - 0014-2999
VL - 619
SP - 25
EP - 32
JO - European Journal of Pharmacology
JF - European Journal of Pharmacology
IS - 1-3
ER -