Neuron location

In the mammalian brain orexins are almost exclusively expressed in a small group of neurons located in the lateral hypothalamus (LH) andperifornical area (PEA)... 

Locus ceruleus Nucleus of norepinephrine-containing neurons located in the brain stem that are responsible for physiologic response to stress and panic. 

The cell bodies of somatic motor neurons are found in the ventral horn. The axons of these neurons exit the CNS through the ventral root of the spinal nerve and innervate skeletal muscles. The two types of motor neurons located in the ventral horn are ... 

The development of antibodies against ChAT allowed the distribution of neurons producing acetylcholine in the nervous system to be revealed (Mesulam et al., 1983 Armstrong et al., 1983 Jones Beaudet, 1987 Vincent Reiner, 1987). In the context of control of wakefulness and REM sleep two groups of cholinergic neurons are of primary importance. Neurons located in the basal forebrain and medial septum provide the cholinergic innervation of the cerebral... 

Histamine-containing neurons, located in the tuberomammillary nuclei (TMN) of the posterior hypothalamus, stimulate cortical activation through... 

The histaminergic neurons have several well-developed primary and secondary dendrites that overlap with each other. Furthermore, long dendrites from histaminergic neurons located close to the mammillary recess or to the basal surface of the mammillary body appear to penetrate into the ependymal layer and make contact with cerebrospinal fluid. Thus, it is likely that neuroactive substances such as cytokines, present in the cerebrospinal fluid, may influence the discharge activity of TMN neurons (Wada et al., 1991). Unlike the dopaminergic neurons, which are known to release dopamine from their dendrites, there is no evidence that these histaminergic dendrites store and/or release HA. 

Two olfactory systems have evolved in terrestrial vertebrates which differ in both their peripheral anatomy and central projections. The main olfactory system is usually conceived as a general analyzer that detects and differentiates among complex chemosignals of the environment (Firestein 2001). Odors are detected by olfactory sensory neurons located in the main olfactory epithelium (MOE) these neurons project to glomeruli in the main olfactory bulb (MOB). The mitral and tufted neurons abutting these MOB glomeruli then transmit olfactory signals to various... 

In humans and other mammals, the sense of smell begins when we inhale some odorant through our nose. The inhaled air enters the nasal cavity where it encounters a large number of olfactory neurons located in the nasal epithelium associated with bony structures located at the rear of this cavity. These bony structures are known as turbinates. In a human, these turbinates create a surface area of a few square inches. In a medium-size dog, in contrast, the turbinates have a surface area several times larger. It is small wonder that dogs have a more acute sense of smell than we do. 

In animal experiments, stimulation of the locus coeruleus, a collection of noradrenalin-producing neurons located bilaterally in the pons area with... 

The tti-adrenoceptors are located at postjunctional (postsynaptic) sites on tissues iimervated by adrenergic neurons. a2-Adrenoceptors having a presynaptic (i.e., neuronal) location are involved in the feedback inhibition of norepinephrine release from nerve terminals (discussed later). a2-Receptors also can occur postjunc-tionally. The (3i-adrenoceptors are found chiefly in the heart and adipose tissue, while (32-adrenoceptors are located in a number of sites, including bronchial smooth muscle and skeletal muscle blood vessels, and are associated with smooth muscle relaxation. 

Although some neurons release more than one type of neu-rotransmltter, many neurons make do with only one. The machinery to make, use, and terminate a specific neurotransmitter can be found only In the neurons that employ it (unless the neurotransmitter molecule has other uses in the body). Serotonin, for example, can be found only in a small number of neurons located In the brain stem. (Since serotonin has other functions, it is also found in other places in the body.) But this tiny number of neurons has widespread projections throughout the brain, making serotonin one of the most important chemicals despite the small number of neurons using it as a neurotransmitter. 

Recently, a method for TMS of the brain has been developed. By using TMS it is possible to noninvasively depolarize neurons located deep in the brain without induction of seizures or pain. Thus, it may be possible to compare behavioral effects of TMS and known effects of repeated ECS and other antidepressants in rats. ECS reverses behavioral despair in the swim test and enhances apomorphine hyperactivity and stereotypy. TMS appears to have similar effects to ECS on reversal of the despair in the swim test. Rapid [25-Hz] TMS but not slow (0.2-Hz) TMS potentiated apomorphine stereotypy. ECS is followed by a postictal inhibitory period for further seizures. In this study, TMS as well as ECS increased the seizure threshold for subsequent stimulation and decreased the duration of subsequent seizure. Rapid [25-Hz] TMS but not slow [5- or 1-Hz) TMS decreases the duration of seizure induced by electrical current. 

In behavioral tests, the actions of peripherally-administered ATP are pro-nociceptive. These nociceptive responses have been suggested to be due to direct activation of peripheral nerve terminals (Hies and Norenberg, 1993). ATP produces depolarization when applied to the cell bodies of primary afferent neurons located within the dorsal root ganglia (DRG) (Jahr and Jessell, 1983). The depolarizing effect of ATP results from the activation of a non-selective cation channel (Bean, 1990) and is blocked by P2 purinoreceptor antagonists (Tsuda et al., 1999), indicating that excitation is mediated via ionotropic P2X purinoreceptors. 

Activation of kappa receptors also produces analgesia, but it simultaneously induces nausea and dysphoria. Kappa receptors are located mainly on pain neurons located in the spinal cord and, to a lesser extent in the brain. They bind to an endogenously occurring ligand called dynorphin. 

Mileykovskiy BY, Kiyashchenko LI, Kodama T, Lai YY, Siegel JM. Activation of pontine and medullary motor inhibitory regions reduces discharge in neurons located in the locus coeruleus and the anatomical equivalent of the midbrain locomotor region. J Neurosci (Online) 2000 20 8551-8558. 

Some 3500 dopaminergic neurons located in the zona compacta of the substantia nigra innervate the entire neostriatum 0>, 7). Within the neostriatum, the axons of these neurons form an extremely dense terminal arborization that can be visualized with fluorescence histochemistry and immunocytochemical techniques ( 8, 9). This terminal arborization contains approximately 1 billion dopaminergic varicosities and forms about 20% of all the varicosities (10) present in the neostriatum. 

The nervous system is divided into two anatomical divisions, the central nervous system (CNS), which is composed of the brain and spinal cord, and the peripheral nervous system, which includes neurons located outside the brain and spinal cord, that is, any nerves that enter or leave the CNS (Figure 3.1). The peripheral nervous system can be further divided into the efferent division, whose neurons carry signals away from the brain and spinal cord to the peripheral tissues, and the afferent division, whose neurons bring information from the periphery to the CNS. 

At rostral levels (Fig. 4), the dorsal and the ventral tiers of the SNc are both located dorsal to the SNr, where they are distributed in two sheets of neurons one on top of the other. Proceeding caudally, the ventral tier of the SNc splits into two parts, one subjacent to the cells of the dorsal tier and the other comprising the dopaminergic neurons located within the SNr. These caudal dopaminergic neurons are also well evident in the mouse (Fig. 8). 

---