Cholinergic and GABAergic forebrain projections to the habenula and nucleus interpeduncularis: surgical and kainic acid lesions.
The forebrain cholinergic and GABAergic projections to the habenula and nucleus interpeduncularis have been investigated by means of surgical and kainic acid lesions. Bilateral transection of the stria medullaris caused a 50% decrease of choline acetyltransferase in both the habenula and nucleus interpeduncularis, and a 65% decrease of glutamate decarboxylase in the habenula. Electrolytic lesions of the posterior septum (nucleus triangularis septi and nucleus septo-fimbrialis) accounted for at least 30-40% decrease of the cholinergic parameter in the habenula and nucleus interpeduncularis. Moreover, the choline acetyltransferase decrease in the habenula appeared restricted to the medial part of the nucleus. Kainic acid injections causing very large neuronal destruction in the nucleus of the diagonal band of Broca, and more than 70% decrease of choline acetyltransferase in the dorsal hippocampus, did not affect the cholinergic parameter in either the medial or lateral habenula or nucleus interpeduncularis. Kainic acid injections in the nucleus entopeduncularis resulted in a 40% decrease of glutamate decarboxylase in the habenula. Kainic acid injections in the nucleus of the diagonal band were accompanied by a 40% decrease of glutamate decarboxylase in the medial subdivision only. The present study points at the nuclei of the posterior septum as the source of a major cholinergic projection to the habenula and nucleus interpeduncularis, and reveals a previously unsuspected GABAergic input from the nucleus of the diagonal band to the medial habenula.
D000109:Acetylcholine / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D004027:Diencephalon / Q000502:physiology*; D004525:Efferent Pathways / Q000502:physiology*; D005968:Glutamate Decarboxylase / Q000378:metabolism; D006651:Histocytochemistry; D007608:Kainic Acid / Q000633:toxicity; D008297:Male; D008473:Median Eminence / Q000201:enzymology; D051381:Rats; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D005680:gamma-Aminobutyric Acid; D002795:Choline O-Acetyltransferase; D005968:Glutamate Decarboxylase; D000109:Acetylcholine; D007608:Kainic Acid