Lateral neurons oscillations

Cermakian I have a general question. In the Drosophila system can we really talk about peripheral and central oscillators, or should we consider the lateral neurons as one clock among many other clocks that are fairly independent ... 

Hardin In the antenna, the oscillator is sufficient for driving that rhythm. It doesn t seem to be affected by the lack of lateral neurons. 

Stanewsky I would hke to return to the question of peripheral versus central oscillators. There is a difference between the lateral neuron clock and the peripheral oscillators. The only rhythm known to persist in flies is the behavioural rhythm, which is driven by the lateral neurons. Whatever other tissue you look at, per and tim expression dampens fast in constant darkness. Do you know anything about the antennal rhythms ... 

Weit It seems that what we have heard about is damped and sustained oscillations, but we haven t yet heard anything telling us whether there are damped or sustained oscillators. So far, very few of these assays have employed single-cell studies. It is conceivable that the main difference between the SCN and other tissues, or between lateral neurons and other tissues, is that those are coupled together by synaptic coupling. 

Young In flies, with behaviour lasting as long as it does, I remember rumours of someone looking at oscillations in lateral neurons specifically. We are making assumptions about how lateral neurons work, but does anyone have data on lateral neurons after 10 days in DD, for example, to show that they really do cycle ... 

The molecular assays in Clk"mAic2As bom fide rhythms with a predominant effect on circadian rhythm amplitude and no more than a modest effect on phase or period. With circadian per and tim enhancers, we observed reduced enhancer activity and a reduced cycling amplitude in a Clk" background, consistent with the role of Clk in regulating these enhancers. Nonetheless, the phase of oscillating bioluminescence is similar to that of wild-type flies. The presence of molecular rhythms contrasts with the absence of detectable behavioural rhythms. We favour the notion that this reflects a level or amplitude reduction below a critical threshold for behavioural rhythmicity. The absence of anticipation of light—dark transitions makes it very unlikely that an effect restricted to the lateral neurons — the absence of the neuropeptide PDF, for example — is primarily responsible for the behavioural phenotypes. This is also because LD behavioural rhythms are largely normal in flies devoid of PDF or the pacemaker lateral neurons (Renn et al 1999). However, we cannot exclude the possibility of selective effects of Clk" on other behaviourally relevant neurons. 

While the abundance of DBT does not oscillate, the subcellular localization of DBT does change throughout the circadian day (Fig. 2). In Drosophila, the subcellular distribution of DBT in the lateral neurons of the brain and in photoreceptor cells of the eye largely follows the changing localization of PER (Kloss et al 2001). In mammals, the pattern of CKl accumulation is also under circadian control the kinase appears to associate initially with mPER and mCRY in the cytoplasm, but it is also found in nuclear complexes and may regulate their movement to the nucleus (Lee et al 2001). 

Pape HC, Pare D, Driesang RB 1998 Two types of intrinsic oscillations in neurons of the lateral and basolateral nuclei of the amygdala. J Neurophysiol 79 205-216... 

The first model based on CICR was proposed by Kuba Takeshita (1981) for Ca oscillations in sympathetic neurons (see Friel Tsien, 1992, for a recent study of Ca oscillations in this type of cell) the role of IP3, unknown at that time, was not taken into account. Dupont and Goldbeter, in collaboration with Berridge, later considered the model shown in fig. 9.4c, of a more general nature, where CICR is initiated by the IP3-mediated build up of cytosolic Ca (Dupont Goldbeter, 1989 ... 

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