The effects of thrombin on cytosolic calcium levels ([Ca2+](cyt)), and on gonadotropin-releasing hormone (GnRH) release, were characterized in cultured GT1-7 neurons. GnRH release from GT1-7 neurons was pulsatile with an average pulse amplitude of 14.3 ± 5.8 pg . min . ml-1 and an average pulse duration of 21.3 ± 4.2 min. The [Ca2+](cyt) response to 0.005 to 0.2 U/ml thrombin was saturable and concentration dependent (EC50 = 0.0268 U/ml). Ethyleneglycotetraacetic acid (EGTA) chelation of extracellular Ca2+ resulted in an ~70% attenuation of thrombin-stimulated increase in [Ca2+](cyt). By use of a special superfusion system, a 5-min exposure to 0.1 U/ml thrombin significantly increased the amplitude (193.2 ± 67.8 pg . min . ml-1; P = 0.001) but not the duration (22.5 ± 2.4 min; P = 0.8) of GnRH release. These results suggest that thrombin increases [Ca2+](cyt) and GnRH release from GT1-7 neurons via specific membrane-bound receptors. Copyright (C) 1999 Elsevier Science Inc.
- GT1-7 cells
- Gonadotropin-releasing hormone
- Intracellular Ca levels
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience