Inhibitory effects of tetrandrine on intracellular free Ca2+ increase induced by glutamate, serotonin and histamine in dissociated retina cells.
The effects of tetrandrine (Tet) on the elevation of intracellular free Ca2+ concentration ([Ca2+]i) induced by glutamate, serotonin and histamine in dissociated rabbit retina cells were studied. The changes of [Ca2+]i were reflected by the fluorescent indicator, Fura-2/AM, employed. In the presence of extracellular Ca2+ (1.3 mM), glutamate, serotonin and histamine significantly increased the [Ca2+]i in a dose-dependent manner. Glutamate (100 microM), serotonin (100 microM) and histamine (200 microM) markedly increased the [Ca2+]i of retina cells by 165%, 126% and 58%, respectively. Tet 30 microM significantly inhibited the increase of [Ca2+]i induced by glutamate (100 microM), serotonin (100 microM) and histamine (200 microM) by 28.0%, 46.8% and 29.0%, respectively. A lower concentration (10 microM) of Tet also produced an inhibitory effect on the increase of [Ca2+]i but was less effective than the Tet 30 microM. In Ca(2+)-free Hank's solution, Tet did not produce a significant inhibitory effect on the increase of [Ca2+]i caused by serotonin and histamine. These results indicate that Tet exercises blocking Ca2+ influx from the extracellular site via NMDA, 5-HT2 and H1-receptor operated Ca2+ channels and has no obvious effect on the Ca2+ release from intracellular Ca2+ stores.
Xuan
B
B
Department of Pharmacology, Nanjing Medical University, People's Republic of China.
Liu
F
F
Zhang
M Y
MY
Xiao
J G
JG
D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D044182:Benzylisoquinolines; D002118:Calcium / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes / Q000378:metabolism; D016257:Fura-2 / Q000031:analogs & derivatives / Q000378:metabolism; D018698:Glutamic Acid / Q000494:pharmacology*; D006632:Histamine / Q000494:pharmacology*; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D011817:Rabbits; D011969:Receptors, Histamine H1 / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D011985:Receptors, Serotonin / Q000378:metabolism; D012160:Retina / Q000187:drug effects / Q000378:metabolism*; D012701:Serotonin / Q000494:pharmacology*
D000470:Alkaloids; D000894:Anti-Inflammatory Agents, Non-Steroidal; D044182:Benzylisoquinolines; D015220:Calcium Channels; D005456:Fluorescent Dyes; D007166:Immunosuppressive Agents; D011969:Receptors, Histamine H1; D016194:Receptors, N-Methyl-D-Aspartate; D011985:Receptors, Serotonin; C049925:fura-2-am; C009438:tetrandrine; D012701:Serotonin; D018698:Glutamic Acid; D006632:Histamine; D002118:Calcium; D016257:Fura-2