GABA(A), GABA(B), AND BENZODIAZEPINE BINDING-SITES IN THE CEREBELLAR CORTEX OF THE RED-EARED TURTLE (PSEUDEMYS-SCRIPTA)

We used receptor autoradiography to ascertain the distribution of GABA(A) and GABA(B) binding sites in the cerebellar cortex of the red-eared turtle (Pseudemys scripta). GABA(A) binding sites were found in both molecular and granule cell layers with highest levels in the granule cell layer. GABA(B) binding sites were found at highest level in the molecular layer. Benzodiazepine binding sites were found in approximately equal abundance in both layers. Little binding of any ligand was seen in the Purkinje cell layer. Our results are similar to those found in mammals and other non-mammalian vertebrates and indicate that the organization of inhibitory pathways of the cerebellar cortex has been conserved in the course of vertebrate evolution.