PURPOSE: The physiologic role of the cellular prion protein (PrPc) is unknown. Mice devoid of PrPc develop normally and show only minor deficits. However, electrophysiologic and histologic alterations found in these mice suggest a possible role for PrPc in seizure threshold and/or epilepsy. METHODS: We tested the sensitivity of PrPc knockout mice to seizures induced by single convulsant or repeated subconvulsant (kindling) doses of pentylenetetrazol (PTZ), and to status epilepticus (SE) induced by kainic acid or pilocarpine. RESULTS: In PTZ kindling, seizure severity progressed faster in the PrPc knockout group, in which 92.8% reached stage 5 or death after 4 days of stimulation, as opposed to 38.4% in wild-type animals. After 10 injections, mortality was 85.7% among knockouts and 15.3% among controls. After a single PTZ injection (60 mg/kg), overall mortality due to seizures was 91% in knockout mice, but only 33% among wild-type animals. Pilocarpine-induced SE (320 mg/kg) caused an 86.7% mortality in knockouts, as opposed to 40% in wild-type animals. Finally, after kainic acid injections (10 mg/kg), 70% of the knockouts developed at least one severe seizure, and 50% showed repetitive seizures, whereas no wild-type animal exhibited observable seizures. CONCLUSIONS: Animals lacking cellular prion protein expression are more susceptible to seizures induced by various convulsant agents. This is perhaps the most striking alteration yet found in PrPc-null mice, who at first analysis appeared to be completely normal. A possible role for PrPc in chronic and idiopathic (familial), secondary, or cryptogenic epilepsies in humans remains to be investigated.
PURPOSE: The physiologic role of the cellular prion protein (PrPc) is unknown. Mice devoid of PrPc develop normally and show only minor deficits. However, electrophysiologic and histologic alterations found in these mice suggest a possible role for PrPc in seizure threshold and/or epilepsy. METHODS: We tested the sensitivity of PrPc knockout mice to seizures induced by single convulsant or repeated subconvulsant (kindling) doses of pentylenetetrazol (PTZ), and to status epilepticus (SE) induced by kainic acid or pilocarpine. RESULTS: In PTZ kindling, seizure severity progressed faster in the PrPc knockout group, in which 92.8% reached stage 5 or death after 4 days of stimulation, as opposed to 38.4% in wild-type animals. After 10 injections, mortality was 85.7% among knockouts and 15.3% among controls. After a single PTZ injection (60 mg/kg), overall mortality due to seizures was 91% in knockout mice, but only 33% among wild-type animals. Pilocarpine-induced SE (320 mg/kg) caused an 86.7% mortality in knockouts, as opposed to 40% in wild-type animals. Finally, after kainic acid injections (10 mg/kg), 70% of the knockouts developed at least one severe seizure, and 50% showed repetitive seizures, whereas no wild-type animal exhibited observable seizures. CONCLUSIONS: Animals lacking cellular prion protein expression are more susceptible to seizures induced by various convulsant agents. This is perhaps the most striking alteration yet found in PrPc-null mice, who at first analysis appeared to be completely normal. A possible role for PrPc in chronic and idiopathic (familial), secondary, or cryptogenic epilepsies in humans remains to be investigated.
Authors: Roger Walz; Rosa Maria R P S Castro; Tonicarlo R Velasco; Carlos G Carlotti; Américo C Sakamoto; Ricardo R Brentani; Vilma R Martins Journal: Cell Mol Neurobiol Date: 2002-06 Impact factor: 5.046
Authors: Silvio M Zanata; Marilene H Lopes; Adriana F Mercadante; Glaucia N M Hajj; Luciana B Chiarini; Regina Nomizo; Adriana R O Freitas; Ana L B Cabral; Kil S Lee; Maria A Juliano; Elizabeth de Oliveira; Saul G Jachieri; Alma Burlingame; Lan Huang; Rafael Linden; Ricardo R Brentani; Vilma R Martins Journal: EMBO J Date: 2002-07-01 Impact factor: 11.598
Authors: Michelle N Valadão; Erica R Coimbra; Michele C Landemberger; Tonicarlo R Velasco; Vera C Terra; Lauro Wichert-Ana; Veriano Alexandre; David Araújo; Ricardo Guarnieri; Vilma R Martins; Antônio Carlos Santos; Américo C Sakamoto; Roger Walz Journal: Neurol Sci Date: 2013-10-05 Impact factor: 3.307
Authors: Claire E Le Pichon; Matthew T Valley; Magdalini Polymenidou; Alexander T Chesler; Botir T Sagdullaev; Adriano Aguzzi; Stuart Firestein Journal: Nat Neurosci Date: 2008-12-21 Impact factor: 24.884
Authors: Alan Rigter; Jan Priem; Drophatie Timmers-Parohi; Jan P M Langeveld; Fred G van Zijderveld; Alex Bossers Journal: BMC Biochem Date: 2009-11-30 Impact factor: 4.059