Browsing by Author "LLADOS, F"

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    ACUTE CHANGES IN VENTILATION AND BLOOD-PRESSURE INDUCED BY INHALATION OF TOBACCO-SMOKE
    (1976) ZAPATA, P; ZUAZO, A; LLADOS, F
    Inhalation of cigarette smoke through a tracheal cannula was induced in cats anesthetized with pentobarbital. Smoking of tobacco cigarettes produced increased ventilation and systemic hypertension, which were found to be due to their nicotine content. Respiratory stimulation and the increase in diastolic pressure were abolished by acute section of buffer nerves, but the mediation of carotid nerves was more important than that of the vagi for evoking reflex hyperventilation. Tobacco smoking induced a marked increase in the frequency of chemosensory impulses recorded from the carotid nerves, an effect due to its nicotine content.
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    DOPAMINE-BETA-HYDROXYLASE ACTIVITY IN NORMAL AND SYMPATHECTOMIZED CAROTID-BODIES
    (1976) MORGADO, E; LLADOS, F; ZAPATA, P
    Normal carotid bodies excised from cats showed DBH [dopamine-.beta.-hydroxylase] values of 5.04 .+-. 0.53 nmol [3H]octopamine formed/h per 100 mg tissue (.hivin.x .+-. S.E.). Values from sympathectomized carotid bodies were not significantly different. While the ganglio-glomerular nerves, providing the sympathetic innervation of the carotid bifurcation, had a high DBH level, this was low in the carotid sinus nerve, providing its sensory innervation. Glomeral DBH may be contained in a special type of noradrenergic glomus cells, distinct from the most common dopaminergic glomus cells.
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    RESPIRATORY AND CIRCULATORY REFLEXES INDUCED BY NICOTINE INJECTIONS - ROLE OF CAROTID-BODY CHEMORECEPTORS
    (1976) ZAPATA, P; ZUAZO, A; LLADOS, F
    I.v. and intracarotid injections of nicotine were delivered to cats anesthetized with pentobarbital. Low doses of nicotine induced reflex hyperventilation and hypertension, mainly due to excitation of carotid body chemoreceptors. The frequency of discharge of carotid nerve chemosensory fibers was increased by nicotine in doses as low as 1 .mu.g/kg when injected i.v. and 50 ng when injected into the carotid artery. Nicotine also activates vagal afferent fibers; some of them produce reflex excitation of the respiratory and vasomotor centers, but others provoke reflex inhibition. High doses of nicotine can act directly upon the medulla provoking acceleration or arrest of ventilation. Nicotine can also induce late changes of b.p. [blood pressure] (delay 5 s or more) which are not mediated by the carotid or vagus nerves.