Glutamic acid decarboxylase isoforms are differentially distributed in the septal region of the rat.

The septal region of the brain consists of a heterogeneous population of GABAergic neurons that play an important role in the generation of hippocampal theta rhythms. While GABAergic neurons employ two isoforms of the enzyme glutamic acid decarboxylase (GAD) for the synthesis of GABA, distribution of GAD isoforms has not been investigated in the septum. Immunohistochemical techniques were used to investigate the expression of GAD enzymes in medial and lateral septum.