Central nervous system midbrain

By immunohistochemistry, a- and p-synucleins are concentrated in nerve terminals, with little staining of somata and dendrites. Ultrastructurally, they are found in close proximity to synaptic vesicles. In contrast,y-synuclein is present throughout nerve cells in many brain regions. In rat, a-synuclein is most abundant throughout telencephalon and diencephalon, with lower levels in more caudal regions. P-Synuclein is distributed fairly evenly throughout the central nervous system, whereas y-synuclein is most abundant in midbrain, pons and spinal cord, with much lower levels in forebrain areas. 

HT3 receptors are located exclusively on neurons and are widely distributed throughout the peripheral and central nervous systems. In the periphery, 5-HT3 receptors are found on autonomic, sensory, and enteric neurons (Fozard 1984). In the central nervous system, 5-HT3 receptors are labeled in cortex, hippocampus, caudate hypothalamus, brain stem, midbrain, and cerebellum, with the highest density in discrete nuclei of the lower brain stem (e.g., dorsal vagal complex and spinal trigeminal nucleus), the area postrema, and substantia gelatinosa at all levels of the spinal cord (Palacios et al. 1991 Waeber et al. 1989). 

CNS agents of the 1,4 benzodiazepine class presumably exert their effects by binding at stereo specific receptors at several sites within the central nervous system (CNS). Alprazolam like other benzodiazepines exerts its anxiolytic action by potentiating GABA activity. GABA is a neurotransmitter which inhibits the CNS activity. Alprazolam acts preferentially in midbrain, ascending reticular formation (which maintains wakefulness) and on limbic system (thought and mental functions). 

A group of cell bodies in the central nervous system of vertebrates. Examples of such groups are the red nucleus in the midbrain, through which impulses are routed for the control of subconscious muscular movements,... 

Rotter A, Birdsall NJ, Field PM, Raisman G. 1979. Muscarinic receptors in the central nervous system of the rat. 11. Distribution of binding of [3H]propylbenzilylcholine mustard in the midbrain and hindbrain. Brain Res 180 167-183. 

NR4A2 is mainly expressed within the central nervous system (CNS) during development and in adult mice and rats. Expression is limited to several brain areas including the cortex, ventral midbrain, brain stem and the spinal cord [5, 28]. NR4A2 expression is detected as early as embryonic day 10.5 in the ventral midbrain in developing dopamine (DA) neurons [29, 30] and expression in these cells continues into adulthood. 

The central nervous system (CNS) of vertebrates is a very complex structure derived from a multistep process involving sequential molecular and morphogenetic events that pattern the epiblast first and the neural plate later. During early gastrulation, the concerted and sequential action of both the anterior visceral endoderm (AVE) and the node and its derivatives (axial mesendoderm, AME, and anterior definitive endoderm, ADE) (Beddington and Robertson, 1999 Bachiller et al., 2000) drives the specification of the anterior neuroectoderm, which subsequently is subdivided in three main territories (forebrain, midbrain, and hindbrain) (Gallera, 1971 Storey et al., 1992 Ruiz i Altaba, 1994 Shimamura and Rubenstein, 1997 Rubenstein and Beachy, 1998). 

The serotonergic neuronal system is one of the most extensive in the central nervous system. The cell bodies of this system are clustered in approximately 10 groups known as Raphe nuclei in the midbrain and lower brain stem. Nevertheless, the axons and terminals permeate every major brain region and the neurons functionally subserve a variety of physiologic functions, including food and water intake, sexual activity, sleep thermoregulation, regressiveness, and blood pressure control. 

The divisions of the cranial central nervous system include the cerebral hemispheres, the diencephalon (thalamus and hypothalamus), the brainstem (midbrain, pons and medulla oblongata) and the cerebellum (Fig. 1.2). Each cerebral hemisphere occupies one half of the cranial vault and can be subdivided into four lobes (frontal, parietal, temporal, occipital), the insula and the limbic lobe. The first four lobes are named for the cranial bones that overlie them. With respect to the floor of the cranial cavity, the frontal lobes lie in the anterior cranial fossa the brainstem and cerebellum occupy the posterior cranial fossa the remaining structures are found either in the middle fossa or within the portion of the cranial vault above the tentorium cerebelli. The insula is covered by the temporal lobe and is not observable unless the temporal lobe is retracted. The hmbic system is a continuous interior... 

The midbrain is of particular importance with regard to auditory and visual reflexes, regulation of arousal, and as a conduit between higher and lower centers of the central nervous system. Consequently, the anatomy of a cross-section of this relatively uncomplicated part of the brainstem will be discussed (Fig. 1.4). The tectum... 

Fig. 1.6 Cross-section illustrating the distribution of blood to the walls of the midbrain. The tectum is supplied by branches of the superior cerebellar artery. The medial aspects of the peduncular and tegmental regions are vascularized by branches of the basUar artery. The lateral peduncular and tegmental regions are supplied by branches of the posterior communicating artery. Note that these small arteries, which enter the walls of the central nervous system from the periphery, are functional end arteries and do not anastomose with adjacent arteries (See also Color Insert)...

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