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BACKGROUND: Previous studies have shown that propofol enhances proliferation of culturedhippocampal precursor cells in vitro and increases proliferation of cultured hippocampal precursorceils inhibited by corticosterone. Because gamma-aminobutyric acid A (GABA-A) receptor is thefunctional target for propofol, the proliferative effects of propofol are thought to take place throughGABA-A receptor.OBJECTIVE: To determine whether propofol enhances proliferation of rat hippocampal precursorcells inhibited by corticosterone by upregulating expression of GABA-A receptor.DESIGN, TIME AND SETTING: A comparative, observational, in vitro experiment was performed atthe Beijing Institute of Pharmacology and Toxicology from April 2005 to April 2006.MATERIALS: Propofol was purchased from AstraZeneca, Italy; corticosterone was purchased fromSigma, USA; bicuculline was purchased from Alexis, Switzerland.METHODS: Hippocampal precursor cells were isolated from newborn Wistar rats and cultured invitro. The second passage of precursor cells was grouped according to the various drugs added tothe culture medium: 0.5 μmol/L propofol; 2.5 μmol/L propofol; 100 μmol/L corticosterone; 10 μmol/Lbicuculline; 100 iμmol/L corticosterone and 0.5 μmol/L propofol; 100 μmol/L corticosterone and2.5 μmol/L propofol; 100 μmol/L corticosterone, 10 μmol/L bicuculline, and 0.5 μmol/L propofol;100 μmol/L corticosterone, 10 μmol/L bicuculline, and 2.5 μmol/L propofol; 100 μmol/Lcorticosterone and 10 μmol/L bicuculline. The cells were cultured for 24 hours with mediumcontaining the respective concentration of drug. The control group consisted of precursor cellsabsent of drug treatment.MAIN OUTCOME MEASURES: The MTT and 3H-TdR incorporation assays were used to detectproliferative effects of propofol and bicuculline on cultured rat hippocampal precursor cells inhibitedby corticosterone. Immunocytochemistry was used to detect GABA-A receptor expression.Enzyme-linked immunosorbent assay was used to quantify GABA-A receptor expression.RESULTS: Propofol, at a concentration of 0.5 and 2.5 μmol/L, increased proliferation of cultured rathippocampal precursor cells inhibited by corticosterone, while bicuculline antagonized the effects ofpropofol (P < 0.05 or P < 0.01). Corticosterone (100 μmol/L) decreased expression of GABA-Areceptor in the hippocampal precursor cells (P < 0.05), and GABA-A receptor expression wasupregulated when propofol (2.5 μmol/L) was added to the culture medium (P < 0.05).CONCLUSION: Low concentrations of propofol increased expression of GABA-A receptor. Theseresults suggest that GABA-A receptor is involved in increased proliferation of cortisone-inhibited rathippocampal precursor cells in vitro.
BACKGROUND: Previous studies have shown that propofol enhances proliferation of cultured hippocampal precursor cells in vitro and increased proliferation of cultured hippocampal precursor cells inhibited by corticosterone. Because gamma-aminobutyric acid A (GABA-A) receptor is the functional target for propofol, the proliferative effects of propofol are thought to take place through GABA-A receptor. OBJECTIVE: To determine whether propofol enhances proliferation of rat hippocampal precursor cells inhibited by corticosterone by upregulating expression of GABA-A receptor. SIGNATURE, TIME AND SETTING: A comparative, observational, in vitro was done atthe Beijing Institute of Pharmacology and Toxicology from April 2005 to April 2006. Majories: Propofol was purchased from AstraZeneca, Italy; corticosterone was purchased from Sigma, USA; bicuculline was purchased from Alexis, Switzerland. METHODS: Hippocampal precursor cells were isolated from newborn Wistar rats and cultured invitro. Th e second passage of precursor cells was grouped according to the various drugs added tothe culture medium: 0.5 μmol / L propofol; 2.5 μmol / L propofol; 100 μmol / L corticosterone; 10 μmol / L bicuculline; L propofol 100 μmol / L corticosterone and 2.5 μmol / L propofol 100 μmol / L corticosterone 10 μmol / L bicuculline 0.5 μmol / L propofol 100 μmol / L corticosterone 10 μmol / L bicuculline 2.5 μmol / L propofol; 100 μmol / L corticosterone and 10 μmol / L bicuculline. The cells were cultured for 24 hours with mediumcontaining the respective concentration of drug. The control group consisted of precursor cells absent of drug treatment. MAIN OUTCOME MEASURES: The MTT and 3H- TdR incorporation assays were used to detect proliferative effects of propofol and bicuculline on cultured rat hippocampal precursor cells inhibited by corticosterone. Immunocytochemistry was used to detect GABA-A receptor expression. Enzyme-linked immunosorbent assay was used to quantify GABA-A receptor expression .RESULTS: Propofol, at a concentration of 0.5 and 2.5 μmol / L, increased proliferation of cultured rathippocampal precursor cells inhibited by corticosterone, while bicuculline antagonized the effects of propofol (P <0.05 or P <0.01) / L) decreased expression of GABA-Areceptor in the hippocampal precursor cells (P <0.05), and GABA-A receptor expression wasupregulated when propofol (2.5 μmol / L) was added to the culture medium concentrations of propofol increased expression of GABA-A receptor. These results suggest that GABA-A receptor is involved in increased proliferation of cortisone-inhibited rathippocampal precursor cells in vitro.