The modulation of action potentials (APs) and high-threshold calcium currents by gamma-aminobutyric acid (GABA) and GABAB receptor agonist baclofen was investigated in identified internally perfused neurons of Lymnaea stagnalis using current-clamp and whole-cell voltage-clamp techniques. GABA (5 x 10(-5) M) and baclofen (5 x 10(-5) M) reversibly reduced overshoot and afterhyperpolarization phase of the action potentials. Application of GABA or baclofen inhibited inward and outward voltage-gated ionic currents. GABA (10(-8)-10(-4) M) was found to suppress high-threshold calcium current in voltage- and dose-dependent manner. These effects were mimicked by baclofen (5 x 10(-5) M) but not by muscimol (5 x 10(-5) M). Inhibition of Ca(2+)-currents could not be prevented by pentylenetetrazole (5 x 10(-5) M) or with pertussis toxin (1 microgram/ml). These results provide evidences for the presence of GABAB receptors in the identified central neurons of Lymnaea stagnalis L.
|Original language||English (US)|
|Number of pages||6|
|Journal||Acta biologica Hungarica|
|State||Published - 1995|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Environmental Science(all)