[1] Charles Univ Prague, Fac Med 1, Inst Physiol, Prague 2, Czech Republic
[2] Charles Univ Prague, Fac Med 1, Dept Psychiat, Prague 12800 2, Czech Republic
[3] Dept Med, Prague 7, Czech Republic
[4] Dalhousie Univ, Dept Physiol & Biophys, Halifax, NS, Canada