ALPHA-SUBUNIT OF CALCIUM CALMODULIN-DEPENDENT PROTEIN-KINASE-II ENHANCES GAMMA-AMINOBUTYRIC-ACID AND INHIBITORY SYNAPTIC RESPONSES OF RAT NEURONS IN-VITRO/

1. Here we report that in acutely isolated rat spinal dorsal horn neur ons, the gamma-aminobutyric acid-A (GABA(A)) receptor can be regulated by calcium/calmodulin-dependent protein kinase II (CaM-KII). Intracel lularly applied, the alpha-subunit of CaM-KII enhanced GABA(A)-recepto r-activated current recorded with the use of the whole cell patch-clam p technique. This effect was associated with reduced desensitization o f GABA responses. 2. GABA-induced currents are also potentiated by cal yculin A, an inhibitor of protein phosphatases 1 and 2A. 3. Convention al intracellular recordings were made from hippocampal CA1 neurons in slices to determine the effect of intracellular application of CaM-KII on inhibitory synaptic potentials evoked by electrical stimulation of the stratum oriens/alveus. The inhibitory synaptic potential was enha nced by CaM-KII; this mechanism may contribute to long-term enhancemen t of inhibitory synaptic transmission and may also play a role in othe r forms of plasticity in the mammalian brain.