Ventral pallidum

Napier T. C., Potter P. E. (1989). Dopamine in the rat ventral pallidum/substantia innominata biochemical and electrophysiological studies. Neuropharmacology 28(7), 757-60. 

Basal forebrain accumbens nuclei, ventral palbdum, bed nucleus of the stria terminahs, diagonal band bed nucleus of the stria terminalis, diagonal band, ventral pallidum... 

Protein identified by IHC in the ventral pallidum, cerebral cortex, the amygdaloid area, the nucleus of the diagonal band, others of rat brain (Shinoda et al., 1989). Less activity in human fetal brain than other tissues assayed by pH] release from 1-androstenedione into water (Doody and Carr, 1989). 

Immunohistochemical localization of the 5-HT2C receptor has been reported by several groups (136,137). In the rat brain, these receptors are found in the olfactory system, CA1 field of the hippocampus, dorsal hippocampal area, several thalamic nuclei, olfactory tubercle, caudate-putamen, ventral pallidum, several areas of the cortex (including piriform and frontal), and dorsal raphe nucleus. 

HT7 receptor acts by inhibiting Ca2+-activated K+ channels. The effect of clozapine to block 5-HT effects on GABAergic neurons in the ventral pallidum might be of importance for its antipsychotic effect (78). 

Bengtson CP, Lee DJ, Osborne PB. Opposing electrophysiological actions of 5-HT on non-cholinergic and cholinergic neurons in the rat ventral pallidum in vitro. J Neurophysiol 2004 92 433-443. 

EP is frequently defined nowadays as GPi (or medial GP) also in rodents, adopting in rodents the subdivision of the GP in two segments (cf. the rat atlases of Paxinos and Watson (1998) and Swanson (1992) cf. also the mouse atlases of Hof et al. (2000) and Paxinos and Franklin (2001)). The majority of neurons of both the GP divisions are large and fusiform or triangular, with very long, thick, smooth and sparsely branching dendrites (see for reviews Heimer et al., 1995, and Gerfen, 2004). The term ventral pallidum refers to the ventral or subcommissural part of the pallidal complex (see Section 7). 

The ventral striatum (NAc and olfactory tubercle) send efferents to the ventral pallidum, which represents a ventral extension of the GP lying below the anterior commissure in the forebrain. The ventral pallidum also receives a dopaminergic innervation from the VTA (Beckstead et al., 1979), and noradrenergic innervation from the locus coeruleus. 

In its close association with the ventral striatum, the ventral pallidum constitutes the ventral striatopallidal system (Heimer and Wilson, 1975), a circuit integrated in a... 

Two anatomically and neurochemically different subdivisions have been described within the ventral pallidum, namely a dorsolateral and a ventromedial compartment (Zham and Heimer, 1988 Zahm, 1989). Recent data based on the combined DAT and TH immunoreactivity at the light and electron microscopic levels have shown that the DATpositive axonal profiles are denser in the lateral than in the medial compartment of the ventral pallidum, whereas the TH-labeled axons show a complementary distribution, with higher density in the medial than in the lateral compartment of the ventral pallidum (Mengual and Pickel, 2004). This organization supports a dualism of the DA action in the ventral striatopallidal pathways. 

In the diencephalon, besides the hypothalamus, dopaminergic fibers have also been detected in the thalamic nuclei and in the habenula. It is interesting to note that in the thalamus dopaminergic fibers are distributed to nuclei that are also recipient of inputs from the ventral pallidum. 

Medium-high density of D2 receptors was found in the islands of Calleja, ventral pallidum, zona incerta, GP, central amygdala, in some cells of the anterior lobe of the pituitary, and at several sites in the forebrain the laterodorsal septal area, hippocampus, subiculum, lateral habenula, STh, lateral mammillary bodies. D2 receptors were also found with a medium-high density in various cortical fields prefrontal, anterior cingulate, entorhinal and perirhinal cortices. In the brain stem, medium-high density of D2 receptors was found in the VTA, SNc, ventral SNr, parabrachial nucleus, superior and inferior colliculi, dorsal raphe nucleus and locus coeruleus. 

Mengual E, Pickel VM (2004) Regional and subcellular compartmentation of the dopamine transporter and tyrosine hydroxylase in the rat ventral pallidum. J Comp Neurol 465 395-409. 

Robertson GS, Jian M (1995) D1 and D2 dopamine receptors differentially increase Fos-like immunoreactivity in accumbal projections to the ventral pallidum and midbrain. Neuroscience 64 1019-1034. 

Johnson K, Churchill L, Klitenick MA, Hooks MS, Kalivas PW (1996) Involvement of the ventral tegmental area in locomotion elicited from the nucleus accumbens or ventral pallidum. J Pharmacol Exp Ther 277(2) 1122—1131. 

Immunoreactivity for parvalbumin and the neurofilament protein SMl-32 identifies the ventral pallidum (Paxinos etal., in press [a]). We retained the term substantia innominata and identified dorsal, ventral (as in Grove, 1988), and basal components with the assistance of G. Alheid. The basal component is marked by some positivity in tyrosine hydroxylase but is negative for SMl-32 (although surrounding areas are positive). 

The concept of ventral pallidum, first proposed by Heimer and his associates, has been the guiding principle for structure/function relations of the basal forebrain (Barragan and Ferreyra-Moyano, 1995 Heimer etal., 1997). The researchers at the University of Virginia and Universidad Nacional de Gordoba have recently carved... 

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