Calcium currents in pyramidal neurons acutely dissociated from the rat frontal cortex: a study by the nystatin perforated patch technique

Abstract

We studied electrical and pharmacological properties of voltage-activated Ca²⁺ currents (I_Ca) in freshly dissoaciated rat frontal cortical pyramidal neurons by using nystatin perforated patch and conventional patch-clamp techniques. Within wither nystatin perofated technique or conventional patch-clamp technique, low voltage-activatedI_Ca (LVAI_Ca) and hihg voltage-activated_Ca (HVAI_Ca) were recorded. However, in conventional whole-cell recording, HVAI_Ca ran down within 5–20 min, whereas the current remained stable for 50 min at least in nystatin perforated patch recording. The HVAI_Ca recorded by nystatin perforated patch technique was further classified to L-type, N-type and a current component resistant to both nicardipine and ω-conotoxin by their current kinetics, voltage- and drug-sensitivities. Present results suggest that the perforated patch technique is a useful method for studying the properties of high voltage-activated Ca²⁺ channels.