Effects of protein synthesis inhibitors on sleep and seizure susceptibility in kindled and nonkindled cats.

This study examined the effects of protein synthesis inhibitors on sleep and seizure susceptibility in kindled and nonkindled cats. Animals were treated with chloramphenicol or its congener, thiamphenicol (150 mg/kg, oral), at 12-hr intervals over a 30-hr period. State pattern variables were monitored continuously during the first 24 hr. At 30 hr, animals were administered convulsive doses of monomethylhydrazine (10 mg/kg, ip), and seizure latencies, measured from the time of drug injection to the onset of tonic—clonic convulsions, were determined. Circadian state pattern percentages for untreated kindled and nonkindled animals agreed with values reported in previous studies. Rapid eye movement (REM) sleep was significantly reduced in animals treated with chloramphenicol, but was unaffected by thiamphenicol administration. Seizure latencies were unaltered in nonkindled cats pretreated with protein synthesis inhibitors; however, seizure susceptibility in kindled animals was significantly enhanced following chloramphenicol administration. Thus, protein synthesis inhibition reduced seizure thresholds only when it was associated with the suppression of REM sleep in animals predisposed to seizures. This finding suggested that the functional stability of neural systems is, to some extent, dependent upon REM related anabolic activity.