Details

Autor(en) / Beteiligte

• Ezure, Kazuhisa
• Otake, Kazuyoshi
• Lipski, Janusz
• Wong She, Richard B.

Titel

Efferent projections of pulmonary rapidly adapting receptor relay neurons in the cat

Ist Teil von

• Brain research, 1991-11, Vol.564 (2), p.268-278

Ort / Verlag

London: Elsevier B.V

Erscheinungsjahr

1991

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• Axonal projections of second order neurons activated by vagal afferent fibers originating from pulmonary rapidly adapting receptors (RARs) were studied electrophysiologically in Nembutal-anesthetized, paralyzed and artificially ventilated cats. Extracellular recordings from these neurons (referred to as ‘RAR-cells’) were made in the commissural subnucleus (COM) of the nucleus of the solitary tract (NTS). They were identified by a combination of stimuli including stimulation of the vagus nerve(s), hyperinflation and deflation of the lungs, and a brief period of ammonia vapor inhalation. A total of 80 RAR-cells were tested for axonal projections to a respiration-related area in the brainstem, either the dorsolateral rostral pons or the dorsal respiratory group (DRG) or the ventral respiratory group (VRG) or the Bötzinger complex (BOT) and/or the spinal cord. Twenty-two of the 47 (47%) RAR-cells tested for ipsilateral pontine projection could be antidromically activated, and in 8 cases evidence for axonal arborization was obtained. Only 1 of the 11 RAR-cells tested for DRG projection, and 1 of the 10 RAR-cells tested for VRG projection, were antidromically activated. No RAR-cells were activated from the BOT ( n = 8) or from the C3–C4 segments of the spinal cord ( n = 11). Bilateral lesions of the COM abolished the reflex responses induced by ammonia inhalation or hyperinflation of the lungs, but not the Hering-Breuer reflex. These results indicate that a pathway from the COM to the rostral pons forms part of the reflex arc originating from RARs.