Expression and regulation of kappa opiate receptors in rat spinal cord-dorsal root ganglion cocultures.
We have been using rat spinal cord-dorsal root ganglion primary cocultures (SC-DG) as a model system for exploring K receptor regulation. During the first 10 days in culture, the total number of opiate receptors increased markedly, reaching a Bmax of 180 fmoles/mg protein for K sites and a Bmax of 50 fmoles/mg protein for mu sites. Following this period of development, the K and mu receptor number did not change significantly. No detectable delta sites were observed at any time of culture. The binding of [3H]diprenorphine to K sites was found to be saturable, of high affinity and stereospecific. After chronic agonist treatment of cultured cells, K receptors did not down-regulate, whereas more than 50% of the mu receptor sites did. Following chronic antagonist treatment, mu receptors were markedly up-regulated (260% of control), while K sites exhibited a weaker up-regulation response (160% of control). These data demonstrate that K opiate receptors are expressed at high concentrations in SC-DG cultures and that contrary to mu receptors in spinal cord and delta receptors in NG10815 cells, K binding sites are less susceptible to modulation following chronic agonist or antagonist treatment. This suggests that K receptors may be regulated by different control mechanisms.
Attali
B
B
Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel.
Saya
D
D
Vogel
Z
Z
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D005048:Etorphine / Q000494:pharmacology; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism*; D009270:Naloxone / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D051381:Rats; D011957:Receptors, Opioid / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D017473:Receptors, Opioid, kappa; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism*; D014158:Transcription, Genetic
D000700:Analgesics; D011759:Pyrrolidines; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D009270:Naloxone; D005048:Etorphine; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer