[Abstract Title]. - Society for Neuroscience

Title: REM sleep insomnia and decreased PPT cholinergic neurons following myocardial
infarction in the rat
Authors: *T. M. BAH 1,2 , F. LAPLANTE 2,4 , S. KALOUSTIAN 1,3 , R. SULLIVAN 4,2 , G.
ROUSSEAU 1,3 , R. GODBOUT 1,2 ;
1 Res., Sacre-Coeur Hosp., Montreal, QC, Canada; 2 Psychiatry, 3 Pharmacol., Univ. of Montreal,
Montreal, QC, Canada; 4 Fernand-Seguin Res. Center, Louis-H Lafontaine Hosp., Montreal, QC,
Canada
Abstract: Introduction: We have already shown that myocardial infarction (MI) in the rat is
followed within a few weeks by cell loss in the limbic system due to apoptosis, together with a
“post MI behavioral syndrome” characterized by signs of anxiety and depression (Wann et al., J.
Psychiatry Neurosci. 2007; 37: 11-16). Here we show that the post MI syndrome is accompanied
by selective losses of Paradoxical (or REM) sleep (PS) and of cholinergic neurons in the
pedunculopontine tegmental area (PPT).
Methods: Ten adult Sprague-Dawley rats were implanted with chronic EEG and EMG
electrodes; baseline sleep was recorded seven days after, for 24h. The following morning MI was
induced by occluding the left coronary artery for 40 minutes in four rats while the six other rats
were used as sham controls. Sleep was recorded again two weeks after MI. At the end of the
protocol, the rats were perfused and quantification of choline acetyltransferase (ChAT)
expressing neurons was carried out in the pedunculopontine tegmental area (PPT) and the
laterodorsal tegmental area (LDT), using immunohistochemistry. Results in both groups of rats
were compared using t-tests for independent samples.
Results: Compared to sham rats, MI rats displayed less total sleep time and less time in PS,
particularly at the light-dark transition. We also found that, compared to sham rats, MI rats
showed a significant reduction (20%) of ChAT neurons in the PPT area, not in the LDT.
Conclusion: The present results extend the apoptotic effects of MI in the limbic system to
brainstem cholinergic area known to control PS. The selective loss of at the light-dark transition
is not typical of anxiety and depression models and this needs to be further investigated.
Disclosures: T.M. Bah , None; F. Laplante, None; S. Kaloustian, None; R. Sullivan,
None; G. Rousseau, None; R. Godbout, None.
Poster
285. Sleep: Molecular, Cellular and Pharmacology I
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 285.22/QQ38
Topic: E.08.c. Sleep: Molecular, cellular, and pharmacology