Substance P containing and cholinergic projections from the habenula.
Electrolytic lesions and surgical transection of the habenulo-interpeduncular-ventrotegmental tract have established the existence of separate habenulo-interpeduncular-ventrotegmental substance P and cholinergic projections. Micro-knife lesions separating the habenula nuclei showed the medial habenular nucleus to be the source of substance P fibres running via the fasciculus retroflexus to the ventral tegmental area. The lateral habenular nucleus receives a substance P projection from the medial habenular nucleus and is the source of cholinergic projection to the interpeduncular nucleus and to the medial habenular nucleus. Lesions of the ventrotegmental-interpeduncular area did not modify the levels of substance P and choline acetyltransferase in the habenula. These observations suggested that there are no substance P or ACh containing afferents to the habenula from the ventrotegmental-interpeduncular area and the accumulation of substance P and AChE proximal to but not caudal to transections of the fasciculus retroflexus confirmed this view.
D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D002799:Cholinergic Fibers / Q000033:anatomy & histology* / Q000201:enzymology; D005455:Fluorescent Antibody Technique; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology / Q000201:enzymology; D051381:Rats; D013373:Substance P / Q000378:metabolism / Q000502:physiology*; D013681:Tegmentum Mesencephali / Q000033:anatomy & histology / Q000201:enzymology; D013787:Thalamic Nuclei / Q000033:anatomy & histology* / Q000201:enzymology
D013373:Substance P; D000110:Acetylcholinesterase