Anatomical association between the DA system and the NT system
| NT Cell Bodies | NT Fibers | NT Receptors | |
|---|---|---|---|
| Origin | |||
| VTA (A10) | (+/++) NT cell bodies concentrated in dorsolateral VTA Colocalized with: colocalized with TH and CCK, very few NT-only neurons DA receptors: D2 autoreceptors | (++) NT fibers NT fibers originate outside the midbrain (preoptic nuclei, lateral hypothalamus, others) | (+++) NTR binding; (+++) NT1 mRNA; (+++) NT2mRNA • 80–90% of NT1 binding is on DA neurons and the majority of DA neurons express NT1 • NT1 are distributed evenly over perikarya and dendrites of DA neurons • low NT2 primarily on non-DA neurons and glia |
| Projection area | |||
| Preguenual and suprarhinal PFC | (−) NT cell bodies | (−) NT fibers (+++) NT/DA | (+++) NTR binding; (++) NT1 mRNA; (−) NT2mRNA • NT1 located pre- and postsynaptically |
| Entorhinal cortex | (−) NT cell bodies | (++) NT: subiculum and VTA (+++) NT/DA | (+++) NTR binding; (++) NT1mRNA; (−) NT2 mRNA • NT1 located pre- and postsynaptically • High NT2 |
| Nucleus accumbens shell | (++) NT cell bodies Projections: medial VP, lateral hypothalamus, preoptic area Colocalized with: GABA DA receptors: D2, D3, and possibly D1 | (++) NT fibers: local axon collaterals, subiculum and ? (++) NT/DA | (++) NTR binding; (−) NT1 mRNA; (++) NT2mRNA • NT1 located pre- and postsynaptically, located on neurons and glia • NT2 moderate |
| Nucleus accumbens core | (++) NT cell bodies Projections: lateral VP, SNc Colocalized with: GABA DA receptors: D2 and probably D1 | (++) NT: local axon collaterals, subiculum and (−) NT/DA | (++) NTR binding; (−) NT1 mRNA; (++) NT2mRNA • NT1 pre- as well as postsynaptically • NT2 moderate |
| Olfactory tubercles | (++) NT cell bodies Projections: (ND) Colocalized with: (ND) DA receptors: (ND) | (++) NT fibers: local axon collaterals and ? ? NT/DA | (+++) NTR binding; (+) NT1 mRNA; (−) NT2mRNA • NT1 located postsynaptically on cell bodies in later II • NT2 low |
| Basolateral nucleus of the amygdala | (−) NT cell bodies | (−) NT fibers (+) NT/DA | (+++) NTR binding; (+) NT1 mRNA; (−) NT2mRNA • NT1 located pre- and postsynaptically |
| Central nucleus of the amygdala | (+++) NT cell bodies Projections: BNST, dorsal vagal nucleus, parabrachial nucleus, and central grey Colocalized with: (ND) DA receptors: (ND) | (+++) NT fibers: local axon collaterals and ? (−) NT/DA | (+++) NTR binding; (++) NT1 mRNA; (−) NT2 mRNA • NT1 few presynaptically, no postsynaptic NT1 detected |
| Lateral septum | (+++) NT cell bodies Projections: Diagonal band of Broca, hypothalamus Colocalized with: (ND) DA receptors: (ND) | (+++) NT: local axon collaterals and ? (++) NT/DA: originate in VTA and diencephalon | (+++) NTR binding; (+++) NT1 mRNA; (−) NT2mRNA • NT1 located mostly presynaptically • NT2 low |
| BNST | (+++) NT cell bodies Projections: dorsal vagal complex, parabrachial nucleus Colocalized with: (ND) DA receptors: (ND) | (+++) NT: CeA, local axon collaterals (ND) NT/DA | (+++) NTR binding; (+++) NT1 mRNA; (++) NT2 mRNA • NT1 located pre- and postsynaptically • NT2 (ND) |
| Origin | |||
| Substantia nigra (A9) Retrorubral field (A8) | (−/+) NT cell bodies Very few NT neurons in medial SNc, SNl, and RRF Colocalized with: NT in medial SNc not colocalized with DA or CCK; NT in SNl or RRF colocalized with DA but not CCK DA receptors: D2 receptors on NT/DA neurons | (+++) NT NT fibers originate outside the midbrain | (+++) NTR; (+++) NT1 mRNA; (+++) NT2 mRNA • 95% of NT1 receptors located on DA neurons • Majority of DA neurons express NT1 • NTRs evenly distributed over perikarya and dendrites • Some NT1 located on non-DAergic terminals possibly originating in the striatum or on glial cells • NT2 low, not on DA neurons |
| Substantia nigra (A9) Retrorubral field (A8) | (−/+) NT cell bodies Very few NT neurons in medial SNc, SNl, and RRF Colocalized with: NT in medial SNc not colocalized with DA or CCK; NT in SNl or RRF colocalized with DA but not CCK DA receptors: D2 receptors on NT/DA neurons | (+++) NT NT fibers originate outside the midbrain | (+++) NTR; (+++) NT1 mRNA; (+++) NT2 mRNA • 95% of NT1 receptors located on DA neurons • Majority of DA neurons express NT1 • NTRs evenly distributed over perikarya and dendrites • Some NT1 located on non-DAergic terminals possibly originating in the striatum or on glial cells • NT2 low, not on DA neurons |
| Projection area | |||
| Premotor, retrosplenial, and visual cortex | (−) NT cell bodies | (ND) NT (−) NT/DA | (−/+) NTR; (−) NT1 mRNA; (−) NT2 mRNA |
| Anterior cingulate cortex | (−) NT cell bodies | (ND) NT (−) NT/DA | (++) NTR; (++) NT1 mRNA; (−) NT2 mRNA • NT1 presynaptically |
| Caudate/putamen | (−/+) NT cell bodies only detectable in ventromedial and ventrolateral aspects Projections: globus pallidus and SNr Colocalized with: GABA, enkephalin, substance P, dynorphin DA receptors: D2 and D1 | (−/+) NT: local axon collaterals (−) NT/DA | (+++) NTR; (−) NT1 mRNA; (−) NT2mRNA • NT1 located presynaptically (mostly in DA terminals) |
| Origin | |||
| Arcuate nucleus + periventricular nucleus | (++) NT cell bodies Colocalized with: TH, reported extent of colocalization varies from rare to frequent DA receptors: D2 autoreceptors | (++) NT (++) NT/DA: local axon collaterals | (++) NTR; (+++) NT1 mRNA; (+++) NT2 mRNA • NT1 locate pre- and postsynaptically • (ND) NT2 |
| Projection area | |||
| Median eminence | (−) NT cell bodies | (++) NT (++) NT/DA: arcuate nucleus, mostly in external layer | (++) NTR; (−) NT1 mRNA; (−) NT2mRNA • NT1 located on terminals and cell bodies |
| Pituitary: intermediate lobe | (−) NT cell bodies | (+) NT: arcuate and periventricular nucleus (ND) NT/DA | (+) NTR; (ND) NT1 mRNA; (ND) NT2mRNA • (ND) NT1 • (ND) NT2 |
Table 2 summarizes the anatomical association of NT with the mesocorticolimbic, nigrostriatal, and diencephalic DA systems in their origin and projection areas (given in column one). The second column summarizes the presence of NT cell bodies, transmitters colocalized with NT, projection areas of NT-ergic neurons and types of DA receptors expressed by these neurons whenever known. NT cell bodies: (−), not detectable; (+), few; (++), moderate; (+++), high; (ND), not determined. The third column indicates the presence of NT or mixed NT/DA fibers and their origin. NT fibers: NT/DA, NT colocalized with DA; (−), not detectable; (+), sparse; (++), moderate; (+++), dense; (ND), not determined. The last column summarizes the density of NTR binding and the expression of NT1 or NT2 mRNA in each of these regions. NT receptors: (−), not detectable; (+), low; (++), moderate; (+++), dense; (ND), not determined. The cellular location of the receptors is given whenever possible.