Commissural afferents innervate glutamate decarboxylase immunoreactive non-pyramidal neurons in the guinea pig hippocampus.
The innervation of GABAergic hippocampal neurons by commissural fibers was investigated in the guinea pig by a combined anterograde degeneration - immunocytochemical technique. Presumed GABAergic neurons were identified by immunocytochemistry for glutamate decarboxylase (GAD) and the commissural fibers by electron-dense degeneration following contralateral transection of the fimbria. Commissural afferents were found to establish asymmetric synaptic contacts with non-pyramidal GAD-immunoreactive neurons located in subpyramidal and suprapyramidal zones of region CA1. The observed connection suggests that inhibition of pyramidal cells may occur in a feed-forward manner as postulated by electrophysiological studies.
D000818:Animals; D005968:Glutamate Decarboxylase; D006168:Guinea Pigs; D006624:Hippocampus / Q000033:anatomy & histology* / Q000502:physiology / Q000648:ultrastructure; D008854:Microscopy, Electron; D009433:Neural Inhibition; D009434:Neural Pathways / Q000033:anatomy & histology; D009435:Synaptic Transmission; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase