1993 Fiscal Year Final Research Report Summary
Various afferent inputs influencing the neuronal control of tracheal smooth muscle
| Project/Area Number |
04670056
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
General physiology
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| Research Institution | Toho University School of Medicine |
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Principal Investigator |
ARITA Hideho Toho University School of Medicine, Associate Professor, 医学部, 助教授 (20075576)
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| Project Period (FY) |
1992 – 1993
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| Keywords | control of breathing / Medulla / Tracheal smooth muscle / Hiccup / Brain ischemia |
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| Research Abstract |
The present study revealed various afferent inputs that influenced the activity of the extrathoracic trachea.
1 Excitation of the peripheral chemoreceptor by intravenous injection of cyanic acid produced a constriction of tracheal smooth muscle.
2 Activation of the central chemoreceptor by intra-vertebral arterial injection of CO_2 saturated saline caused tracheal constriction.
3 Intravertebral injection of N_2 saturated saline elicited a dilatation of the trache, indicating that ischemia of the brainstem causes tracheal dilation.
4 Stimulation of the pulmonary stretch receptor by lung inflation evoked a relaxation of tracheal tone. The lung inflation after vagotomy resulted in a paradoxical response, i.e., a constriction of the trachea.
5 Excitation of the irritant receptor of the upper airway produced the increased activity of the tracheal smooth muscle.
6 Electrical stimulation of the proximal end of the femoral nerves elicited the tracheal dilatation.
The present study also demonstrated that a hiccup-like response (a brief powerful inspiratory effort against glottic closure) were generated by electrical stimulation to a limited area within the medullary reticular formation of the cat. The effective sites were localized in the region lateral to the nucleus ambiguus. This finding indicates that there is a neuronal network coordinating the hiccup reflex within the lower brainstem.
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