Identification of c-Fos immunoreactive brainstem neurons activated during fictive mastication in the rabbit

• In the present study we used the expression of the c-Fos-like protein as a "functional marker" to map populations of brainstem neurons involved in the generation of mastication. Experiments were conducted on urethane-anesthetized and paralyzed rabbits. In five animals (experimental group), rhythmical bouts of fictive masticatory-like motoneuron activity (cumulative duration 60-130 min) were induced by electrical stimulation of the left cortical "masticatory area" and recorded from the right digastric motoneuron pool. A control group of five animals (non-masticatory) were treated in the same way as the experimental animals with regard to surgical procedures, anesthesia, paralysis, and survival time. To detect the c-Fos-like protein, the animals were perfused, and the brainstems were cryosectioned and processed immunocytochemically. In the experimental group, the number of c-Fos-like immunoreactive neurons increased significantly in several brainstem areas. In rostral and lateral areas, increments occurred bilaterally in the borderzones surrounding the trigeminal motor nucleus (Regio h); the rostrodorsomedial half of the trigeminal main sensory nucleus; subnucleus oralis-gamma of the spinal trigeminal tract; nuclei reticularis parvocellularis pars alpha and nucleus reticularis pontis caudalis (RPc) pars alpha. Further caudally-enhanced labeling occurred bilaterally in nucleus reticularis parvocellularis and nucleus reticularis gigantocellularis (Rgc) including its pars-alpha. Our results provide a detailed anatomical record of neuronal populations that are correlated with the generation of the masticatory motor behavior.

Nyckelord

Anesthesia

Animals

Brain Stem/*metabolism

Data Interpretation; Statistical

Efferent Pathways/cytology/physiology

Electric Stimulation

Immunohistochemistry

Male

Mastication/*physiology

Masticatory Muscles/innervation/physiology

Microelectrodes

Motor Cortex/physiology

Motor Neurons/physiology

Neurons/*metabolism

Paralysis/physiopathology

Proto-Oncogene Proteins c-fos/*metabolism

Rabbits

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)