- Title
- Central integration of the autonomic cardiorespiratory response to nasopharyngeal stimulation in the rabbit
- Creator
- White, Saxon William
- Relation
- Brain Research Vol. 87, Issue 2-3, p. 171-179
- Publisher Link
- http://dx.doi.org/10.1016/0006-8993(75)90413-8
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 1975
- Description
- Environmental disturbances provoke in the intact animal a variety of autonomic responses each of which may be shown to be a function of the input profile and its central integration. In the rabbit, the nasal inhalation of small amounts of irritants such as smoke or ammonia vapour is followed by apnoea in expiration, a rise in arterial pressure, vagal bradycardia and widespread sympathetic adrenergic vasoconstriction resulting in a marked restriction of blood flow in over 90 ~ of the soft tissue mass. The trigeminal nerve initiates the apnoea, and the arterial baroreceptors and sudden loss of lung inflation both contribute to the cardiac slowing. The olfactory nerves do not play a significant role in the cardiovascular disturbance, and the effects are not a function of chemicals absorbed from the respiratory tract or of stimulation of optic nerves or receptors of the face and lower respiratory tract. The current studies were undertaken in unanaesthetized rabbits to examine the role of different brain regions in the strong autonomic activation evoked by nasopharyngeal stimulation. In addition, the separate components of the input profile were studied in relation to the heart rate and mesenteric vasoconstrictor responses, which were used as indices of autonomic excitation mechanisms. The effects of nasal inhalation of cigarette smoke were first examined in spontaneously breathing pontine (decerebrate), thalamic and sham-operated rabbits in which the carotid sinus and aortic nerves were intact, and in similar preparations when they were sectioned. Then in the same animals under conditions of controlled ventilation the separate effects of smoke stimulation without apnoea, and of apnoea without smoke, were studied. The results suggest that both the trigeminal and lung inflation components of the input profile cause activation of heart rate and vasoconstrictor neurones through mechanisms that operate at both bulbospinal and suprabulbar levels, and that convergence of these inputs with the arterial baroreceptor input serves to facilitate the autonomic responses.
- Subject
- apnoea; trigeminal nerves; carotid sinus; aortic nerves; smoke reflex; autonomic response; nasophayngeal stimulation
- Identifier
- http://hdl.handle.net/1959.13/938937
- Identifier
- uon:12703
- Identifier
- ISSN:0006-8993
- Language
- eng
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