Enhancement of tonic and phasic events of rapid eye movement sleep following bilateral ibotenic acid injections into centralis lateralis thalamic nucleus of cats.
The excitotoxin ibotenic acid (1.2-2.6 microliters of 50 micrograms/microliters) was injected bilaterally into the thalamic centralis lateralis nucleus of chronically implanted cats in order to study the effects of tonic excitation followed by destruction of perikarya on the sleep-waking cycle and its electrographic correlates. Ibotenate injections were performed under mild ketamine anaesthesia. Immediately afterwards, the animals showed behavioural arousal accompanied first by ocular nystagmiform movements and then by pontogeniculooccipital waves. By 6-10 h post-injection, the numbers of rapid eye movement sleep episodes, but not their duration, increased compared to the preinjection control period. The injection sites were histologically confirmed using conventional Thionin stains. Additional control was provided by retrograde transport of wheat-germ agglutinin conjugated with horseradish peroxidase. The present results suggest that a population of neurons important for ocular saccades, pontogeniculooccipital waves, and the state of desynchronized sleep is present in the internal medullary lamina, in particular in the centralis lateralis nuclei.
Marini
G
G
Istituto di Fisiologia Umana II, Facoltà di Medicina, Università degli Studi di Milano, Italy.
Gritti
I
I
Mancia
M
M
D000818:Animals; D001370:Axonal Transport; D002415:Cats; D004569:Electroencephalography; D004576:Electromyography; D004585:Electrooculography; D005133:Eye Movements / Q000187:drug effects*; D005829:Geniculate Bodies / Q000187:drug effects / Q000502:physiology; D006735:Horseradish Peroxidase; D007051:Ibotenic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D008845:Microinjections; D009334:Neck Muscles / Q000502:physiology; D012895:Sleep, REM / Q000187:drug effects / Q000502:physiology*; D013787:Thalamic Nuclei / Q000187:drug effects / Q000502:physiology*; D013788:Thalamus / Q000033:anatomy & histology / Q000502:physiology; D013997:Time Factors; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D014909:Wheat Germ Agglutinins
D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D014909:Wheat Germ Agglutinins; D007051:Ibotenic Acid; D006735:Horseradish Peroxidase