Long-lasting effects of feline amygdala kindling on monoamines, seizures and sleep.
This report describes the relationship between monoamines, sleep and seizures before and 1-month after amygdala kindling in young cats (<1 year old; n=8; six female and two male). Concentrations (fmoles of norepinephrine or NE, dopamine or DA and serotonin or 5-HT) were quantified in consecutive, 5-min microdialysis samples (2 microl/min infusion rate) from amygdala and locus ceruleus complex (LC) during four, 6-8-h polygraphic recordings before (n=2) and 1 month post-kindling (n=2); 5-min recording epochs were temporally adjusted to correspond to dialysate samples and differentiated according to dominant sleep or waking state (lasting > or =80% of 5-min epoch) and degree of spontaneous seizure activity (number and duration of focal versus generalized spikes and spike trains and behavioral seizure correlates). Post-kindling records in each cat were divided into two groups (n=1 record each) based on higher or lower spontaneous EEG and behavioral seizure activity and compared to pre-kindling records. We found: (1) before and after kindling, NE and 5-HT but not DA concentrations were significantly lower in sleep than waking at both sites; (2) after kindling, each cat showed cyclic patterns, as follows: (a) higher NE, 5-HT and DA concentrations accompanied increased seizure activity with delayed sleep onset latency and increased sleep fragmentation (reduced sleep state percentages, number of epochs and/or epoch duration) in one recording versus (b) lower monoaminergic concentrations accompanied reduced seizure activity, rapid sleep onset and reduced sleep disruption in the other recording. The alternating, post-kindling pattern suggested "rebound" effects which could explain some controversies in the literature about chronic effects of kindling on monoamines and sleep-waking state patterns.
Shouse
M N
MN
Department of Veterans Affairs, Greater Los Angeles Health Care System (151A3), Sepulveda, CA 91343, USA. nshouse@ucla.edu
Staba
R J
RJ
Saquib
S F
SF
Farber
P R
PR
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D002415:Cats; D004298:Dopamine / Q000378:metabolism*; D004569:Electroencephalography; D005260:Female; D007696:Kindling, Neurologic / Q000502:physiology*; D008125:Locus Coeruleus / Q000187:drug effects / Q000502:physiology; D008297:Male; D017551:Microdialysis; D009638:Norepinephrine / Q000378:metabolism*; D012640:Seizures / Q000503:physiopathology*; D012701:Serotonin / Q000378:metabolism*; D012890:Sleep / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology; D012895:Sleep, REM / Q000502:physiology; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology
D012701:Serotonin; D004298:Dopamine; D009638:Norepinephrine