Effect of electrical stimulation of the nucleus of the solitary tract on the development of electrical amygdaloid kindling in the cat.
OBJECTIVE
This work analyzed the effect of electrical stimulation of the nucleus of the solitary tract (NTS) on the development of electrical amygdaloid kindling (AK) in freely moving cats.


METHODS
Nine male adult cats with implanted electrodes in both amygdalae (basolateral nucleus), both lateral geniculate bodies, left NTS, and both prefrontal cortices were used. Electromyogram and electrooculogram also were recorded. The AK was performed every 24 h (1-s train, 1-ms pulses, 60 Hz, 300-600 microA). The NTS was stimulated previously for 1 min (0.5-ms pulses, 30 Hz, 150-300 microA), just before the AK at 10:00 a.m., and then every 60 min, 4 times, from 11:00 a.m. to 2:00 p.m. On different days, all NTS stimulation was suspended, and AK was continued until stage VI kindling was reached.


RESULTS
Behavioral changes produced by the stimulation of the NTS were blinking, immobility periods with upward sight, licking, and swallowing. Animals with simultaneous stimulation of NTS and AK did not reach stage VI, remaining in behavioral stages I-III. Stage VI was reached after NTS stimulation was intentionally suspended. The amplitude, duration, and the propagation of the amygdaloid afterdischarge did not exhibit progressive evolution during NTS stimulation. A regression analysis was performed between the number of days with only AK stimulation and days with simultaneous NTS stimulation, which showed a positive correlation (values of r = 0.84).


CONCLUSIONS
Our results suggest that NTS stimulation interferes with the development of convulsive evolution and secondary generalization. This delay effect may be due to the activation of the locus ceruleus and some areas of the midbrain reticular formation, among other structures, which has been demonstrated to inhibit experimental convulsive seizures.
Division of Neuroscience Research, Instituto Nacional de Psiquiatría "Ramón de la Fuente," SSA and Psychology Faculty, Universidad Nacional Autónoma de México (UNAM), México.
Victor M
VM
Magdaleno-Madrigal
Alejandro
A
Valdés-Cruz
David
D
Martínez-Vargas
Adrián
A
Martínez
Salvador
S
Almazán
Rodrigo
R
Fernández-Mas
Augusto
A
Fernández-Guardiola
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002415:Cats; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000706:statistics & numerical data; D005829:Geniculate Bodies / Q000502:physiology; D007696:Kindling, Neurologic / Q000502:physiology*; D008125:Locus Coeruleus / Q000502:physiology; D008297:Male; D017397:Prefrontal Cortex / Q000502:physiology; D012044:Regression Analysis; D012154:Reticular Formation / Q000502:physiology; D012640:Seizures / Q000209:etiology / Q000517:prevention & control*; D017552:Solitary Nucleus / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology*