GLUTAMATE, GABA, CALBINDIN-D(28K) AND PARVALBUMIN IMMUNOREACTIVITY INTHE PULVINAR-LATERALIS POSTERIOR COMPLEX OF THE CAT - RELATION TO THEPROJECTION TO THE CLARE-BISHOP AREA

Neurons of the pulvinar-lateralis posterior complex (Pul-LP) containin g glutamate (Glu) and GABA, as presumed neurotransmitters, and calbind in- D28k (calbindin) and parvalbumin (PV), as Ca-binding proteins, wer e identified in the cat by using immunohistochemical methods. In vibra tome sections, neurons immunoreactive (IR) to each of the four antibod ies were observed throughout the Pul-LP. In semithin sections, GABA-IR neurons were also PV-IR but not calbindin-IR and some of them also co -localized Glu. The Glu-IR neurons which were negative for GABA co-loc alized calbindin but not PV. The neurons of the Pul-LP projecting to t he Clare-Bishop area (CB) in the suprasylvian gyrus were identified wi th a retrogradely transported tracer and the sections were then immuno stained for Glu, GABA, calbindin and PV. Only Glu- and calbindin-IR ne urons were retrogradely labeled. These results show that, if calbindin and PV have a Ca-binding role, the presumably excitatory Glu-IR neuro ns projecting to the CB area use calbindin whereas the presumably inhi bitory GABA-IR neurons are intrinsic and use PV. This relationship imp lies that these proteins probably have other roles specifically relate d to the kind of agonist to be released at the neuron.