Enhancement excitation

In focal epilepsies a number of functional and morphological changes are observed which may act in concert to support enhanced excitability. Such changes have been intensively investigated in order to develop targets for drug design. 

Mutations of the NaVl. 4 channel gene cause various types of muscle diseases, including hyperkalemic periodic paralysis, paramyotonia congenita, myotonia fluctuans, acetazolamide-sensitive myotonia. Mutations disiupt inactivation and cause both myotonia (enhanced excitability) and attacks of paralysis (inexcitability resulting from depolarization). 

Fig. 6 Modified Jablonski diagram for illustrating metal-fluorophore interactions, (a) the transition of dye excited by the incident light, (b) the enhanced excitation according to enlarged electromagnetic field, (c) the fluorescent emission of dye molecule, (d) the nonradiative relaxation, (e) the enhanced emission of the fluorophores and metal coupling in far field. Reproduced with permission from Ref. [77]...

The classification of NMDA antagonists as nonaddictive drugs was based on early assessments, which, in the case of PCP, have recently been questioned. In fact, animal research shows that PCP can increase mesolimbic dopamine concentrations and has some reinforcing properties in rodents. Concurrent effects on both thalamocortical and mesolimbic systems also exist for other addictive drugs. Psychosis-like symptoms can be observed with cannabinoids, amphetamines, and cocaine, which may reflect their effects on thalamocortical structures. For example, cannabinoids, in addition to their documented effects on the mesolimbic dopamine system, also enhance excitation in cortical circuits through presynaptic inhibition of GABA release. 

Clinical investigations to date have focussed on effects of adenosine in experimentally-induced pain as well as clinical pain states. These studies have shown that adenosine administration reduces pain primarily in situations that involve enhanced excitability and nociceptive transmission in the CNS. Since centrally-mediated enhanced excitability is considered to be an important factor in chronic pain conditions, adenosine-induced pain relief in patients with neuropathic pain suggests that adenosine and adenosine analogs are of special importance for future research. 

II. ELECTRON TRANSFER A. Enhanced Excited State Redox Reactivity... 

Compounds of enhanced excitability are used as sensitizers. When introduced into a reaction system of a donor and an acceptor, the sensitizer absorbs light. The sensitizer itself does not undergo bond breaking or isomerization and acts only as an oxidant or a reducer with regard to the substrate. 

According to the Forster cycle, if the longest wavelength electronic transition of the deprotonated form is of lower energy compared to that of the protonated form (red-shifted electronic absorption or emission spectrum of the deprotonated form with reference to the protonated-form spectrum), the molecule has enhanced excited-state acidity (i.e., the pK a of the molecule is lower than pKa). Equation (1) provides a quick and effective method for evaluating a molecule for its ESPT behavior. 

Jagodic MM, Pathirathna S, Nelson MT et al. (2007) Cell-specific alterations of T-type calcium current in painful neuropathy enhance excitability of sensory neurons. J Neurosci 27(12) 3305-3316... 

In section 6.3 2, the reproducibility of the PEL layer-by-layer technique and of the NP deposition was validated by the small standard deviation values obtained for Xjes absorption values for the NPs. This also applies to the enhancement study discussed above. The enhanced excitation spectra shown in figure 6.4 exhibit standard deviations that are less than 4%, which underlines again the high degree of reproducibility of the PEL, NP and dye deposition techniques. 

The presence of MEF, MEP and Metal-Enhanced superoxide anion radical generation in the same system seems surprising at first, as these processes are effectively competitive and ultimately provide a route for deactivation of electronic excited states. As recently shown by the authors, simultaneous photophysical mechanisms can be present within the same system when enhanced absorption effects of the fluorophore near to silver are present (i.e. an enhanced excitation rate). In this case, enhanced absorption of Acridine near-to the plasmon resonant particles facilitates MEF, MEP, ME Oa and also Metal-Enhanced superoxide generation simultaneously within the same system. Aaidine showed an enhanced absorption spectra near-to silver, similar to other probes reported by the authors, in essence acridine absorbs more light. ... 

Of the 25 animal phyla, almost half are worms. Thus, it is not at all surprising that some worms contain toxins. The nemertines are a phylum of over 800 known species which resemble flatworms but are active predators on crustaceans and other worms. This phylum is exceptionally toxic among the various worm phyla. The Heteronemertine side possesses peptide toxins which appear to be only defensive, as these animals have no means of injecting a venom. The peptides include neurotoxins, which enhance excitability of nerve membranes, and cytolysins, which permeabilize and destroy cell membranes. Members of the Hoplonemertine class inject a venom into their prey using a mineralized stylet located in their proboscis, which is also used to immobilize the prey. Their toxins are alkaloids similar to nicotine which in minute amounts paralyze crustaceans and annelid worms and primarily activate nicotinic acetylcholine receptors. Another well-known worm toxin is nereistoxin, a disulfide-containing alkaloid which also binds to nicotinic... 

We described earlier the essence of both the innate and acquired drives as a state of specific activation (active focus) in a special population of subcortical and cortical neurons, respectively (see Fig. 11 in Knoll 1969). In the light of the enhancer regulation concept, we may characterize the active focus as an endogenous enhancer substance-induced enhanced excitability in a circumscribed population of mesencephalic and telencephalic neurons that persists until the goal has been reached. 

The rat with the performance detailed in Protocol 1 behaved as usual on March 4 and 5. The duration of the first reaction, as always, was a longer one on both March 4 (12 01") and March 5 (10 27"). This is the characteristic warming up behavior of the glass-cylinder-seeking rats (see Knoll 1969, for review). A longer time is obviously needed until the state of enhanced excitability is reached in the proper group of cortical neurons which operate as the active focus, the cortical representation of the drive. 

The photophysics and photochemistry of bis-2-(9-anthryl)-ethyl glutamate and pivalate have been employed as a pair of models of different polymeric systems with the same luminescent chromophores.An ingenious method which has been used successfully to enhance excitation transfer in solid polymer is the introduction of intervening anthryl groups along a polymer chain... 

NEUROTRANSMITTERS Transmitters may produce minimal effects on bioelectric properties, yet activate or inactivate biochemical mechanisms necessary for responses to other circuits. Alternatively, the action of a transmitter may vary with the context of ongoing synaptic events— enhancing excitation or inhibition, rather than operating to impose direct excitation or inhibition. Each chemical substance that fits within the broad definition of a transmitter may therefore require operational definition within the spatial and temporal domains of a specific ceU-ceU circuit. Those same properties may not necessarily be generalized to other cells contacted by the same presynaptic neurons differences in operation may relate to differences in postsynaptic receptors and the mechanisms by which an activated receptor produces its effects. 

In conclusion, three-dimensional periodic nanostructures containing erbium ions have been fabricated based on artificial opal matrices. Their photo luminescence efficiency was found to be higher as compared to a reference glass sample. Possible reasons responsible for enhancement include enhanced excitation efficiency due to increase in efficient absorption length and modification of spontaneous decay of ions in a periodic lattice due to redistribution of photon density of states. 

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