scholarly journals Descending projections from thesubstantia nigra pars reticulatadifferentially control seizures

2019 ◽  
Vol 116 (52) ◽  
pp. 27084-27094 ◽  
Author(s):  
Evan Wicker ◽  
Veronica C. Beck ◽  
Colin Kulick-Soper ◽  
Catherine V. Kulick-Soper ◽  
Safwan K. Hyder ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Pedunculopontine Nucleus ◽  
Audiogenic Seizures ◽  
Substantia Nigra Pars Reticulata ◽  
Partial Seizures ◽  
Absence Seizures ◽  
Intermediate Layers ◽  
Generalized Seizures ◽  
Efferent Projection ◽  
Descending Projections

Three decades of studies have shown that inhibition of thesubstantia nigra pars reticulata(SNpr) attenuates seizures, yet the circuits mediating this effect remain obscure. SNpr projects to the deep and intermediate layers of the superior colliculus (DLSC) and the pedunculopontine nucleus (PPN), but the contributions of these projections are unknown. To address this gap, we optogenetically silenced cell bodies within SNpr, nigrotectal terminals within DLSC, and nigrotegmental terminals within PPN. Inhibition of cell bodies in SNpr suppressed generalized seizures evoked by pentylenetetrazole (PTZ), partial seizures evoked from the forebrain, absence seizures evoked by gamma-butyrolactone (GBL), and audiogenic seizures in genetically epilepsy-prone rats. Strikingly, these effects were fully recapitulated by silencing nigrotectal projections. By contrast, silencing nigrotegmental terminals reduced only absence seizures and exacerbated seizures evoked by PTZ. These data underscore the broad-spectrum anticonvulsant efficacy of this circuit, and demonstrate that specific efferent projection pathways differentially control different seizure types.

Lamotrigine in Absence and Primary Generalized Epilepsies

1997 ◽  
Vol 12 (1_suppl) ◽  
pp. S29-S37 ◽  
Author(s):  
Mohamad A. Mikati ◽  
Gregory L. Holmes
Keyword(s):  
Young Patients ◽  
The United States ◽  
Seizure Type ◽  
Newly Diagnosed ◽  
Partial Seizures ◽  
Open Label ◽  
Absence Seizures ◽  
Generalized Seizures ◽  
Clonic Seizures ◽  
Eeg Recordings

Although lamotrigine has been approved in the United States as adjunctive therapy for partial seizures in patients older than 12 years, there is increasing evidence that it is just as effective, if not more effective, in the treatment of generalized seizures. A large number of open-label studies and some single-blind data, all using lamotrigine as add-on therapy in patients with previously refractory generalized seizures, are available. Controlled studies, some on newly diagnosed, previously untreated patients with generalized seizures are ongoing. Investigations have demonstrated that patients with the following generalized seizure types improve with lamotrigine add-on therapy: Typical and atypical absence, atonic, generalized tonic-clonic, myoclonic, and clonic seizures. Response rates, defined as the percentage of patients with better than 50% reduction in seizure frequency, have been, depending on seizure type, in the range of 30% to 56%, with 0 to 33% of the patients becoming seizure free. The best responses have been noted in typical and atypical absences, and atonic seizures. Children and adults appear to have comparable responses. In addition, add-on studies in patients with specific, previously refractory, epilepsy syndromes have demonstrated that the best improvement in seizure control occurs in patients with petit mal epilepsy, "other symptomatic" generalized epilepsies, and in Lennox-Gastaut syndrome, followed by patients with other myoclonic epilepsies, myoclonic absence and West syndrome. Many previously refractory patients are able to achieve lamotrigine monotherapy. However, patients with nonprogressive myoclonic epilepsy have little, if any, response. Early data from ambulatory encephalographic (EEG) recordings in patients with previously refractory absence seizures, and from controlled studies on patients with newly diagnosed typical absence seizures, appear to confirm the efficacy of lamotrigine in those patients. Controlled studies are ongoing in patients with absence seizures, in patients with generalized tonic-clonic seizures, and in patients with Lennox-Gastaut syndrome. Dosing in generalized seizures is similar to that for partial seizures. Because of the shorter half-life of lamotrigine in children, as compared to adults, higher (mg/kg) doses are often needed in young patients. We conclude that lamotrigine is a promising drug for absence and primary generalized seizures in both children and adults. (J Child Neurol 1997;12(Suppl 1):S29-S37).

L-DOPA induziert oszillierende Aktivität in der Substantia nigra Pars reticulata in einem Dyskinesiemodell der Ratte

2005 ◽  
Vol 32 (S 1) ◽  
Author(s):  
W Meissner ◽  
P Ravenscroft ◽  
R Reese ◽  
D Harnack ◽  
B Bioulac ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Substantia Nigra Pars Reticulata

Microtrasplante de células mesencefálicas fetales en estriado y substantia nigra pars reticulata simultáneamente de ratas hemiparkinsonianas. Estudio conductual

2000 ◽  
Vol 30 (12) ◽  
pp. 1122
Author(s):  
Lisette Blanco Lezcano ◽  
Nancy Pavón Fuentes ◽  
Raúl Macías González ◽  
Lázara Castillo Díaz ◽  
Carmen Díaz ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Substantia Nigra Pars Reticulata
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