Characterization of high affinity neurotensin receptor NTR1 in HL-60 cells and its down regulation during granulocytic differentiation.
1. We investigated responses to neurotensin in human promyelocytic leukaemia HL-60 cells. 2. Neurotensin increased the cytosolic calcium concentration ([Ca2+]i) in a concentration-dependent manner and also produced inositol 1,4,5-trisphosphate (InsP3). 3. Among the tested neurotensin analogues, neurotensin 8-13, neuromedin-N, and xenopsin also increased [Ca2+]i, whereas neurotensin 1-11 and neurotensin 1-8 did not elicit detectable responses. 4. SR48692, an antagonist of NTR1 neurotensin receptors, blocked the neurotensin-induced [Ca2+]i increase, whereas levocabastine, which is known as an NTR2 neurotensin receptor antagonist, did not attenuate the neurotensin-evoked effect. 5. The expression of NTR1 neurotensin receptors was confirmed by Northern blot analysis and reverse transcriptase-polymerase chain reaction (RT-PCR). 6. During 1.25% dimethylsulfoxide (DMSO)-triggered granulocytic differentiation of HL-60 cells, the neurotensin-induced [Ca2+]i rise became gradually smaller and completely disappeared 4 days after treatment with DMSO. The mRNA level for neurotensin receptors was also decreased after differentiation. 7. The results show that HL-60 cells express NTR1 neurotensin receptors and suggest that granulocytic differentiation involves transcriptional regulation of the receptors resulting in down-regulation of the neurotensin-induced signalling.
Choi
S Y
SY
Department of Life Science, Pohang University of Science and Technology, Republic of Korea.
Chae
H D
HD
Park
T J
TJ
Ha
H
H
Kim
K T
KT
D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation; D000242:Cyclic AMP / Q000096:biosynthesis; D015536:Down-Regulation; D006098:Granulocytes / Q000737:chemistry* / Q000166:cytology; D018922:HL-60 Cells / Q000737:chemistry*; D006801:Humans; D009496:Neurotensin / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D018028:Receptors, Neurotensin / Q000032:analysis*
D011720:Pyrazoles; D011804:Quinolines; D018028:Receptors, Neurotensin; C079087:SR 48692; D009496:Neurotensin; D000242:Cyclic AMP; D002118:Calcium