TY - JOUR
T1 - Dynorphin A1-17-induced feeding
T2 - Pharmacological characterization using selective opioid antagonists and antisense probes in rats
AU - Silva, Robert M.
AU - Grossman, Henya C.
AU - Hadjimarkou, Maria M.
AU - Rossi, Grace C.
AU - Pasternak, Gavril W.
AU - Bodnar, Richard J.
PY - 2002
Y1 - 2002
N2 - Ventricular administration of the opioid dynorphin A1-17 induces feeding in rats. Because its pharmacological characterization has not been fully identified, the present study examined whether a dose-response range of general and selective opioid antagonists as well as antisense oligodeoxynucleotide (AS ODN) opioid probes altered daytime feeding over a 4-h time course elicited by dynorphin. Dynorphin-induced feeding was significantly reduced by a wide range of doses (5-80 nmol i.c.v.) of the selective κ1-opioid antagonist nor-binaltorphamine. Correspondingly, AS ODN probes directed against either exons 1 and 2, but not 3 of the κ-opioid receptor clone (KOR-1) reduced dynorphin-induced feeding, whereas a missense oligodeoxynucleotide control probe was ineffective. Furthermore, AS ODN probes directed against either exons 1 or 2, but not 3 of the κ3-like opioid receptor clone (KOR-3/ORL-1) also attenuated dynorphin-induced feeding. Although the selective μantagonist β-funaltrexamine (20-80 nmol) reduced dynorphin-induced feeding, an AS ODN probe directed only against exon 1 of the μ-opioid receptor clone was transiently effective. Neither general (naltrexone, 80 nmol) nor δ (naltrindole, 80 nmol)-selective opioid antagonists were particularly effective in reducting dynorphin-induced feeding, and an AS ODN probe targeting the individual exons of the δ-opioid receptor clone failed to significantly reduce dynorphin-induced feeding. These converging antagonist and AS ODN data firmly implicate the κ1-opioid receptor and the KOR-1 and KOR-3/ORL-1 opioid receptor genes in the mediation of dynorphin-induced feeding.
AB - Ventricular administration of the opioid dynorphin A1-17 induces feeding in rats. Because its pharmacological characterization has not been fully identified, the present study examined whether a dose-response range of general and selective opioid antagonists as well as antisense oligodeoxynucleotide (AS ODN) opioid probes altered daytime feeding over a 4-h time course elicited by dynorphin. Dynorphin-induced feeding was significantly reduced by a wide range of doses (5-80 nmol i.c.v.) of the selective κ1-opioid antagonist nor-binaltorphamine. Correspondingly, AS ODN probes directed against either exons 1 and 2, but not 3 of the κ-opioid receptor clone (KOR-1) reduced dynorphin-induced feeding, whereas a missense oligodeoxynucleotide control probe was ineffective. Furthermore, AS ODN probes directed against either exons 1 or 2, but not 3 of the κ3-like opioid receptor clone (KOR-3/ORL-1) also attenuated dynorphin-induced feeding. Although the selective μantagonist β-funaltrexamine (20-80 nmol) reduced dynorphin-induced feeding, an AS ODN probe directed only against exon 1 of the μ-opioid receptor clone was transiently effective. Neither general (naltrexone, 80 nmol) nor δ (naltrindole, 80 nmol)-selective opioid antagonists were particularly effective in reducting dynorphin-induced feeding, and an AS ODN probe targeting the individual exons of the δ-opioid receptor clone failed to significantly reduce dynorphin-induced feeding. These converging antagonist and AS ODN data firmly implicate the κ1-opioid receptor and the KOR-1 and KOR-3/ORL-1 opioid receptor genes in the mediation of dynorphin-induced feeding.
UR - http://www.scopus.com/inward/record.url?scp=0036228610&partnerID=8YFLogxK
U2 - 10.1124/jpet.301.2.513
DO - 10.1124/jpet.301.2.513
M3 - Article
C2 - 11961051
AN - SCOPUS:0036228610
SN - 0022-3565
VL - 301
SP - 513
EP - 518
JO - Journal of Pharmacology and Experimental Therapeutics
JF - Journal of Pharmacology and Experimental Therapeutics
IS - 2
ER -