Further characterization of neurotensin receptor desensitization and down-regulation in clone N1E-115 neuroblastoma cells

Mitsuhiko Yamada, Misa Yamada, Elliott Richelson

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Murine neuroblastoma clone N1E-115 cells possess neurotensin receptors that are coupled to polyphosphoinositide hydrolysis and cyclic guanosine 3′,5′-monophosphate (cGMP) formation. These responses rapidly desensitize and these receptors rapidly down-regulate nearly completely in about 15 min. Although neurotensin is rapidly degraded by peptidases, in this study we show that at 37° neurotensin (100 nM) in the absence of peptidase inhibitors caused this rapid desensitization and down-regulation (32 ± 5 and 24 ± 2% of control, respectively) of neurotensin receptors in N1E-115 cells. In addition, we demonstrated that this desensitization, resensitization, down-regulation and recovery of binding sites were temperature dependent. These data suggest that a certain degree of phospholipid fluidity or activity of some enzymes is required for these processes to occur. After addition of sodium nitroprusside or ionomycin to cells, cGMP increased in desensitized cells to the same degree as in control cells. Additionally, desensitization and down-regulation occurred in the absence of a change in the affinity of neurotensin for the remaining sites. These data suggest that desensitization is not caused by changes in nitric oxide synthesis, guanylyl cyclase activity or receptor affinity, but predominantly by a decrease in receptor number.

Original languageEnglish (US)
Pages (from-to)2149-2154
Number of pages6
JournalBiochemical Pharmacology
Volume45
Issue number10
DOIs
StatePublished - Apr 25 1993

ASJC Scopus subject areas

  • Pharmacology

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