Expression of type 1 metabotropic glutamate receptors in Purkinje neurons of mice

Expression of functional type 1 metabotropic glutamate receptors (mGluR1) was studied in Purkinje neurons in cerebellar slices of mice. Extracellular application of 100 μM of a specific activator of G protein-coupled mGluR, (1S, 3R)-ACPD, triggered a transient elevation of [Ca2+]i in Purkinje neurons. The amplitudes of [Ca2+]i transients in the dendrites of Purkinje neurons were considerably higher than those in the somata, whereas the amplitudes of glutamate-triggered [Ca2+]i transients were similar in these cellular compartments. This suggests the preferential localization of mGluR and/or InsP3-sensitive Ca2+ stores in the dendrites of Purkinje neurons. By applying a single-cell reverse-transcriptase polymerase chain reaction (RT-PCR) technique, we also demonstrated that mRNA, responsible for the expression of mGluR1 type of glutamate receptors, is transcribed in Purkinje neurons; these receptors are likely to be responsible for (1S,3R)-ACPD-evoked calcium signalling.