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Keywords:

  • 5-HT7 receptor;
  • human glioblastoma;
  • astrocytes;
  • glial cells;
  • SB-269970
  • Serotonin 5-HT7 receptors are present in astrocytes. Understanding their role in this type of cell would greatly benefit from the identification of astroglial cell lines expressing this receptor type.

  • The aim of the present study was to assess the expression of native 5-HT7 receptors and 5-HT7 receptor mRNA in a number of human glioblastoma cell lines, by means of cAMP measurements, Western blot analysis and reverse transcriptase–polymerase chain reaction (RT–PCR) analysis.

  • 5-Hydroxytryptamine (5-HT), 5-carboxamidotryptamine (5-CT), 5-methoxytryptamine (5-MeOT) and 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) induced concentration-dependent stimulations of cAMP accumulation in the human glioblastoma cell lines, U-373 MG, U-138 MG, U-87 MG, DBTRG-05MG, T98G, H4, CCF-STTG1 and Hs 683. The rank order of potency was 5-CT>5-HT=5-MeOT≫8-OH-DPAT.

  • The effect of 5-CT was inhibited in a concentration-dependent manner by the selective 5-HT7 receptor antagonist SB-269970 in all human glioblastoma cells. Schild analyses yielded slope factors close to unity (0.89–1.13) and pA2 values of 8.69–9.05.

  • Western blot analysis revealed the presence of immunoreactive bands corresponding to the human 5-HT7 receptor in extracts of all human glioblastoma cell lines.

  • The presence of the three splice variants of the 5-HT7 receptor (5-HT7(a/b/d)) was visualized by RT–PCR analysis with specific primers in all human glioblastoma cell lines.

  • In conclusion, human glioblastoma cell lines express functional 5-HT7 receptors and the three splice variants of the corresponding mRNA. These cell lines could serve as model systems of native 5-HT7 receptors in glial cells to investigate their putative role in processes like release of neurotrophic factors or inflammatory cytokines.

British Journal of Pharmacology (2004) 143, 404–410. doi:10.1038/sj.bjp.0705936