Neurons types

Nicotinic receptors (nicotinic acetylcholine receptors, nACHR) exist not only in the membrane of vertebrate skeletal muscle at the synapse between nerve and muscle (muscle-type nAChR) but also at various synapses throughout the brain, mainly at presynaptic positions (neuronal-type nAChR). Whereas the muscle-type nAChR is precisely composed of two a 1-subunits, one (3 -subunit, one y -subunit and one y -subunit (adult)... 

Eehner In string mutants, not everything works. We have heard from Bill Chia that the first neuroblast divisions follow a very stereotyped program that is also realized after transplantation or in vitro. If you do not allow divisions, the program is not realized and late neuron types are never specified. 

Each neurotrophic factor influences the growth and development of a specific group of neuronal types, with some cells being sensitive to several such factors. Many sustain specific neuronal populations whose death underlines various neurodegenerative diseases. This raises the possibility that these regulatory molecules may be of benefit in treating such diseases. Results from early clinical trials have been at best mixed, but many remain optimistic that neurotrophic factors may provide future effective treatments for some currently incurable neurodegenerative conditions. 

Odorants are thought to bind to integral membrane receptors on the cilia of the olfactory sensory neurons. The receptors are thought to he specific different olfactory neuron types recognize different odorants that share certain characteristics (Buck, 1993). The odorant receptors transduce signals via interactions with G-proteins (so-called because guanosine trisphosphate is involved in their activation). These G-protein-coupled exhibit seven hydrophobic domains (Fig. 5.6). Variation in the amino acid sequence of the transmembrane domain may account for specificity and selectivity of odor reception. 

In the adrenal medulla and the ganglia of parasympathetic and sympathetic nerves, the neurotransmission is mediated by acetylcholine. On the postsynaptic membranes the transmitter activates the neuronal-type of the nicotinic acetylcholine receptor. This receptor type is in fact a sodium channel, its activation leads to a sodium influx and a membrane depolarization. A pharmacological interference at the... 

The BZs predominately bind to and (Oj GABA receptors. Type I (wi) GABA receptors are concentrated in the cerebellum and cortical layers they have a high affinity for triazolopyridazines and P-carbolines, and primarily occur on postsynaptic neurons. Type II (coj) receptors are also found in high numbers in the cortical layers, as well as in the hippocampus, striatum, and spinal cord. These receptors occur mainly on axons or terminals of the striatonigral pathways (Lo et ah, 1983 Ballenger, 1995). The type III (CO3) receptors are found mainly in the cerebellum and may play a role in alcohol-induced ataxia and incoordination (Luddens et ah, 1990). 

In female Heliothis sp. (Lepidoptera) moths, four colocated receptor neurone types were identified, of which three types responded most strongly to the inducible compounds ( )- -ocimene and ( , )-a-farnesene. The fourth type responded most strongly to geraniol, which is a common floral volatile [383]. 

Nn Neuronal type, ganglion receptor CNS postganglionic cell body, dendrites Pentamer with and subunits only, eg, ( 4)2( 2)3 (CNS) or cx3 tx5(B2)3 (ganglia) Na +, K+ depolarizing ion channel... 

Neurotropic factors of dopaminergic neurons may represent a potential neuroprotective therapy for Parkinson s disease. Apart from nerve growth factor (NGF), the family of the neurotrophins subsumes at the present time BDNF, neurotrophin-3 (NT-3), and neurotrophin-4/5 (NT-4/5). However, the concept of neurotrophic factors as specific, target-derived molecules, each acting on distinct neuronal types, has to be modified because of their high degree of pleiotropism and a... 

Distler P. G. and Boeckh J. (1997b) Synaptic connections between identified neuron types in the antennal lobe glomeruli of the cockroach, Periplaneta americana II. Local multiglomerular interneurons. J. Comp. Neurol. 383, 529-540. 

The 5-HT1A receptors are coupled to potassium and calcium channels. Intracellular current-clamp recordings in slices containing the DR established that the 5-HT-mediated inhibition involved an increase in potassium conductance, which exhibits inward rectification (18,58). This induced a membrane hyperpolarization leading to a decrease in action potential frequency. Similar responses to 5-HT1A receptor activation have been reported in other neuronal types, such as hippocampal pyramidal cells (16,59) or 5-HT neurons of the caudal raphe nuclei (60). 

In cortical neurons, 5-HT application excited and inhibited different cortical neurons (82,83), although the predominant effect of 5-HT was an inhibition of spontaneous firing (82,84-86). Similar actions have been described in other neuronal types such as midbrain periaqueductal gray neurons (87) and hippocampal pyramidal neurons (88-90). 

Sano H, Yasoshima Y, Matsushita N, Kaneko T, Kohno K, Pastan I, Kobayashi K (2003) Conditional ablation of striatal neuronal types containing dopamine D2 receptor disturbs coordination of basal ganglia function. J Neurosci 23 9078-9088. 

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