Abstract
We have investigated the effects of somatostatin (SRIF) and the linear octapeptide BIM-23056 on changes in intracellular calcium ion concentration ([Ca2+]i) and on the formation of inositol-1,4,5-trisphosphate (Ins(1,4,5)P3) in CHO-K1 cells transfected with the human recombinant SRIF sst5 receptor. SRIF elicited concentration-dependent increases in [Ca2+]i, with a pEC50 of 7.02 +/- 0.06, while BIM-23056 (1 x 10(-7) M) behaved not as an agonist but as a potent, surmountable antagonist of these increases in [Ca2+]i. The SRIF concentration-effect curve for increases in [Ca2+]i was shifted rightward producing an estimated pKB for the antagonist of 8.0. BIM-23056 (1 x 10(-7) M) also significantly attenuated Ins(1,4,5)P3 increases due to SRIF, but had no effect on either basal or uridine 5'-triphosphate (UTP) (1 x 10(-4) M) stimulated increases in the levels of [Ca2+]i or Ins(1,4,5)P3.
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- Akbar M., Okajima F., Tomura H., Majid M. A., Yamada Y., Seino S., Kondo Y. Phospholipase C activation and Ca2+ mobilization by cloned human somatostatin receptor subtypes 1-5, in transfected COS-7 cells. FEBS Lett. 1994 Jul 11;348(2):192–196. doi: 10.1016/0014-5793(94)00603-2. [DOI] [PubMed] [Google Scholar]
- Hoyer D., Bell G. I., Berelowitz M., Epelbaum J., Feniuk W., Humphrey P. P., O'Carroll A. M., Patel Y. C., Schonbrunn A., Taylor J. E. Classification and nomenclature of somatostatin receptors. Trends Pharmacol Sci. 1995 Mar;16(3):86–88. doi: 10.1016/s0165-6147(00)88988-9. [DOI] [PubMed] [Google Scholar]
- Jenkinson D. H., Barnard E. A., Hoyer D., Humphrey P. P., Leff P., Shankley N. P. International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification. IX. Recommendations on terms and symbols in quantitative pharmacology. Pharmacol Rev. 1995 Jun;47(2):255–266. [PubMed] [Google Scholar]
- Patel Y. C., Srikant C. B. Subtype selectivity of peptide analogs for all five cloned human somatostatin receptors (hsstr 1-5). Endocrinology. 1994 Dec;135(6):2814–2817. doi: 10.1210/endo.135.6.7988476. [DOI] [PubMed] [Google Scholar]
- Rees S., Coote J., Stables J., Goodson S., Harris S., Lee M. G. Bicistronic vector for the creation of stable mammalian cell lines that predisposes all antibiotic-resistant cells to express recombinant protein. Biotechniques. 1996 Jan;20(1):102-4, 106, 108-10. doi: 10.2144/96201st05. [DOI] [PubMed] [Google Scholar]
- Yamada Y., Kagimoto S., Kubota A., Yasuda K., Masuda K., Someya Y., Ihara Y., Li Q., Imura H., Seino S. Cloning, functional expression and pharmacological characterization of a fourth (hSSTR4) and a fifth (hSSTR5) human somatostatin receptor subtype. Biochem Biophys Res Commun. 1993 Sep 15;195(2):844–852. doi: 10.1006/bbrc.1993.2122. [DOI] [PubMed] [Google Scholar]