TY - JOUR
T1 - Evidence for delta receptor mediation of [D-Pen2,D-Pen5]-enkephalin (DPDPE) analgesia in mice.
AU - Heyman, J. S.
AU - Mosberg, H. I.
AU - Porreca, F.
PY - 1986
Y1 - 1986
N2 - Possible involvement of cerebral delta opioid receptors in antinociceptive processes was studied in a test utilizing heat as the noxious thermal stimulus. The investigation focused on selective agonists and antagonists for mu and delta opioid receptors. Morphine and [D-Ala2,NMPhe4, Gly-ol]enkephalin (DAGO) were used as agonists for the mu receptor while [D-Pen2,D-Pen5]enkephalin (DPDPE) was the agonist for the delta receptor. Two approaches were employed: first, the intracerebroventricular (i.c.v.) analgesic activity of the agonists was determined in the absence, and in the presence of graded i.c.v. doses of the selective delta antagonist, ICI 174,864 (N,N diallyl-Tyr-Aib-Aib-Phe-Leu-OH) (where Aib is alpha-aminoisobutyric acid); second, acute tolerance to morphine was produced and the possible presence of acute cross-tolerance between subcutaneous (s.c.) morphine and the delta agonist investigated. ICI 174,864 antagonized the analgesia produced by DPDPE, but not that resulting from morphine or DAGO. Morphine pretreatment resulted in the development of acute tolerance to i.c.v. morphine, and acute cross-tolerance to i.c.v. DAGO, but not to i.c.v. DPDPE. These results provide evidence that both cerebral delta and mu opioid receptors are responsible for the mediation of analgesia in tests utilizing heat as the nociceptive stimulus.
AB - Possible involvement of cerebral delta opioid receptors in antinociceptive processes was studied in a test utilizing heat as the noxious thermal stimulus. The investigation focused on selective agonists and antagonists for mu and delta opioid receptors. Morphine and [D-Ala2,NMPhe4, Gly-ol]enkephalin (DAGO) were used as agonists for the mu receptor while [D-Pen2,D-Pen5]enkephalin (DPDPE) was the agonist for the delta receptor. Two approaches were employed: first, the intracerebroventricular (i.c.v.) analgesic activity of the agonists was determined in the absence, and in the presence of graded i.c.v. doses of the selective delta antagonist, ICI 174,864 (N,N diallyl-Tyr-Aib-Aib-Phe-Leu-OH) (where Aib is alpha-aminoisobutyric acid); second, acute tolerance to morphine was produced and the possible presence of acute cross-tolerance between subcutaneous (s.c.) morphine and the delta agonist investigated. ICI 174,864 antagonized the analgesia produced by DPDPE, but not that resulting from morphine or DAGO. Morphine pretreatment resulted in the development of acute tolerance to i.c.v. morphine, and acute cross-tolerance to i.c.v. DAGO, but not to i.c.v. DPDPE. These results provide evidence that both cerebral delta and mu opioid receptors are responsible for the mediation of analgesia in tests utilizing heat as the nociceptive stimulus.
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M3 - Article
C2 - 2828989
AN - SCOPUS:0022841681
SN - 1046-9516
VL - 75
SP - 442
EP - 445
JO - NIDA research monograph
JF - NIDA research monograph
ER -