Prepulses

Similar effects can arise from an inappropriate zero cross level in a CFD. If the zero cross level is too close to the signal baseline, the zero cross comparator may oscillate and produce a double structure in the IRF. Therefore the CFD parameters should be checked before a PMT is suspected of producing prepulses. 

In general prepulses do not cause major problems in TCSPC measurements. Even if the corresponding peak in the instrument response function (IRF) cannot be suppressed, e.g. because maximum counting efficiency is required, the deconvolution with the actual IRF delivers correct results. 

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NMR Spectroscopy. All proton-decoupled carbon-13 spectra were obtained on a General Electric GN-500 spectrometer. The vinylldene chloride isobutylene sample was run at 24 degrees centigrade. A 45 degree (3.4us) pulse was used with a Inter-pulse delay of 1.5s (prepulse delay + acquisition time). Over 2400 scans were acquired with 16k complex data points and a sweep width of +/- 5000Hz. Measured spin-lattice relaxation times (Tl) were approximately 4s for the non-protonated carbons, 3s for the methyl groups, and 0.3s for the methylene carbons. 

Figure 2.4 Noradrenergic inhibition of Ca " currents and transmitter release in sympathetic neurons and their processes, (a) Inhibition of currents through N-type Ca " channels by external application of noradrenaline (NA) or by over-expression of G-protein P y2 subunits, recorded from the soma and dendrite of a dissociated rat superior cervical sympathetic neuron. Currents were evoked by two successive 10 ms steps from —70 mV to OmV, separated by a prepulse to -1-90 mV. Note that the transient inhibition produced by NA (mediated by the G-protein Go) and the tonic inhibition produced by the G-protein Piy2 subunits were temporarily reversed by the -1-90 mV depolarisation. (Adapted from Fig. 4 in Delmas, P et al. (2000) Nat. Neurosci. 3 670-678. Reproduced with permission), (b) Inhibition of noradrenaline release from neurites of rat superior cervical sympathetic neurons by the 2-adrenoceptor stimulant UK-14,304, recorded amperometrically. Note that pretreatment with Pertussis toxin (PTX), which prevents coupling of the adrenoceptor to Gq, abolished inhibition. (Adapted from Fig. 3 in Koh, D-S and Hille, B (1997) Proc. Natl. Acad. Sci. USA 1506-1511. Reproduced with permission)...

K/2 refers to the test potentials where the conductance increase has reached one half of its maximal value y /2 to the prepulse membrane potential at which the current response to a 50 mV test potential is 50% of its maximum value. Muscle data are from [43,64], photoreceptor data from [41]. 

Schizophrenia Prepulse inhibition Improves prepulse inhibition [56]... 

Figure 3 Rodent pharmacodynamic effects versus CbjU for 6. Dashed lines represent a twofold separation from the in vitro functional assay EC50 (122 nM, dashed arrow). mSLA, mouse spontaneous locomotor activity mPPI, mouse prepulse inhibition DRC, dose-response curve SD, single dose. (See Color Plate 4.3 in the Color Plate Section.)...

D5-dopamine receptor Reduced agonist induced locomotion, startle, and prepulse inhibition [71 ]... 

Low afterpulsing due to ion or photon feedback to the photocathode and low prepulsing due to photoelectron generation from dynodes. The lack of a direct line of... 

Auditory Startle reflex Prepulse modulation Rat Colley et al.195... 

Attentional or cognitive impairments have also been observed in rodent models of nicotine withdrawal. These include impaired performance of a test of sustained attention (Shoaib and Bizarro 2005), disrupted contextual fear conditioning (Davis and Gould 2007 Davis et al. 2005), disrupted operant behaviors (Vann et al. 2006), and decreased prepulse inhibition, a test of selective attention (Semenova et al. 2003). 

Semenova S, Markou A (2003) Clozapine treatment attenuated somatic and affective signs of nicotine and amphetamine withdrawal in subsets of rats exhibiting hyposensitivity to the initial effects of clozapine, Biol Psychiatry 54 1249-1264 Semenova S, Bespalov A, Markou A (2003) Decreased prepulse inhibition during nicotine withdrawal in DBA/2J mice is reversed by nicotine self-administration. Eur J Pharmacol 472 99-110... 

Fig. 10. Sequence for the assessment of magnetization transfer (MT) effects. Images recorded without (a) and with MT prepulses (b) have to be subtracted. In the presented example a standard gradient-echo sequence is used for MT imaging. The MT prepulse is Gaussian-shaped with a flip angle of 600° and 1.5 kHz off-resonance frequency.

Fig. 20. (a) Magnetization transfer effect on water signal in TA using prepulse series with 0°, 400° and 800° amplitude (from left to right) as described in the text, (b) Magnetization transfer ratios of water (MTR ) for TA (left) and SOL (right). 

Spectral series for determination of MTR in TA is shown in Fig. 20a, indicating a strong signal decrease caused by MT preparation, dependent on the MT-prepulse amplitude. However, no significant differences in MTRw were found between the two muscle types examined (see Fig. 20b). 

Altered startle reactivity and attenuation of the inhibition of the startle reflex by an acoustic prepulse has been observed in psychiatric patients, e.g. in schizophrenia (Braff et al. 1978). Disrupted prepulse inhibition in rats can be normalized by antipsychotics and this paradigm is being used as an animal model for drug development. Interestingly, a2c-KO mice had enhanced startle responses, diminished prepulse inhibition, and shortened attack... 

Sallinen J, Haapalinna A, Viitamaa T, Kobilka BK, Scheinin M (1998) Adrenergic Ojc-receptors modulate the acoustic startle reflex, prepulse inhibition, and aggression in mice. J. Neuroscience 18 3035-3042 Sallinen J, Haapalinna A, Viitamaa T, Kobilka BK, Scheinin M (1998) D-amphetamine and L-5-hydroxytryptophan-induced behaviours in mice with genetically-altered expression of the a2c-adrenergic receptor subtype. Neuroscience 86 959-965... 

Dulawa SC, Hen R, Scearce-Levie K, Geyer M (1997) Serotonin IB receptor modulation of startle reactivity, habituation, and prepulse inhibition in wildtype and serotonin IB knock-out mice. Neiuoreport 132 125-134... 

Ornitz, E.M., Russell, A.T., Gabikian, R, Gehricke, J.G., and Guthrie, D. (2000) Prepulse inhibition of startle, intelligence and familial primary nocturnal enuresis. Acta Paediatr 89 475-481. 

Braff, DX., Swerdlow, N.R., Geyer, MA Symptom correlates of prepulse inhibition deficits in male schizophrenic patients. Am. J. Psychiatry 156, 596-602, 1999. 

Paylor, R. and Crawley, J. N. (1997) Inbred strain differences in prepulse inhibition of the mouse startle response. Psychopharmacology (Bed) 132, 169-180. 

Zamponi GW, Bourinet E, Nelson D, Nargeot J, Snutch TP (1997) Crosstalk between G proteins and protein kinase C mediated by the calcium channel alphal subunit. Nature 385 442-6 Zamponi GW, Snutch TP (1998a) Decay of prepulse facilitation of N type calcium channels during G protein inhibition is consistent with binding of a single Gbeta subunit. Proc Natl Acad Sci US A 95 4035-9... 

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