SUBCELLULAR-DISTRIBUTION OF RYANODINE RECEPTOR-LIKE AND CALCIUM ATPASE-LIKE IMMUNOREACTIVITY IN BRAIN-STEM AND CEREBELLAR NEURONS OF RAT AND GUINEA-PIG

Monoclonal antibodies against ryanodine receptor (5C3) and calcium ATP ase (D12) of skeletal muscle sarcoplasmic reticulum were used in an im munoelectron microscopic study of cerebellar Purkinje cells and neuron s of the hypoglossal and dorsal motor nuclei of the vagus (DMV) from r at and guinea-pig. All neurones were labelled with D12 and all, except rat DMV, labelled with 5C3. Most labelling was on smooth endoplasmic reticulum within 500 nm of the plasmalemma where Ca2+-activated Ca2+ r elease would rapidly increase cytosolic calcium following a small Ca2 influx across the plasmalemma.