The actions of the excitatory amino acid ibotenate were investigated in postnatal rat hippocampal neurons. In neurons voltage clamped at negative membrane potentials using low-chloride internal solutions, ibotenate responses consist of an inward cationic current and two outward currents. The inward current is inhibited by 2-amino-5-phosphonovalerate (APV), a selective N-methyl-d-aspartate (NMDA) antagonist. The two outward currents consist of a picrotoxin and bicuculline-sensitive chloride current and a slowly developing calcium activated potassium current. The bicuculline sensitive current appears to be the product of contamination of ibotenate samples with the γ-aminobutyric acid (GABA) agonist muscimol and not the result of a direct action of ibotenate.
- Chloride current
- Voltage clamp