Thursday, March 22, 2012

Sleep meeting update

Last week end I was at the Meeting of the Italian Society for Sleep Research:
Some very interesting preliminary data were presented, probably more of which to be  seen in Paris in September, at the meeting of the European Sleep Research Society.
Here just a few highlights from the meeting

1. Sleep deprivation and cortical excitability

Interesting confirming data on the effect of sleep deprivation on cortical excitability were presented. Cortical evoked potentials were progressively potentiated by sleep deprivation, but also the topography of the cortical activation during the test were altered in sleep deprived subjects.

2. Sleep and prions

Very interesting data on sleep changes in a murine model of Fatal Familial Insomnia (FFI) were presented. FFI is a prionic disease (on of the few discovered in humans), caused by a mutation in the prionic protein (PrP),  that leads to death and causes  dysregulation of the sleep-wake cycle, autonomic nervous system activity and circadian rhythm. The presented data showed how the co-presence of the wild type PrP with the mutated PrP has protective effects on the sleep dysregulation but that the mice KO for the PrP don't show any alteration of the sleep cycle. To conclude, only mice with only the mutated PrP showed the disease.
This is very interesting, it opens a lot of question of what really is the role of the PrP and also suggest the the mutated PrP could produce its effects not disrupting the regular PrP functions, but maybe acting on some different target.

3.  Sleep and Cannabinoids

Data on sleep and cardiovascular phenotype in mice KO for the cannabinoid receptor 1 (CB1) were presented. While sleep 24h structure appear to be affected by the absence of CB1 receptors, the most interesting data were on cardiovascular regulation in CB1 KO mice exposed to an high fat diet. Arterial pressure and hear rate results significantly elevated during the subjective day, suggesting a tonically elevated sympathetic outflow 

4.  Orexin blockade and thermoregulation

The acute blockade of lateral hypothalamic neurons in rodents exposed to a moderate cold environment, produces a temporary mild hypothermia that is compensated before the effect of the inhibition is over, suggesting that orexin neurons may play a role in the thermoregulatory response to acute cold exposure, but that they are not necessary. The same blockade did not produced any change in body temperature at thermoneutrality.