Relation between peripheral chemoreceptors stimulation and pulmonary arterial blood pressure in rats

As interactions between peripheral chemoreceptors stimulation (PCS) and pulmonary vasomotor tone remain controversial, experiments were made in rats in order to clear up the effects of PCS on pulmonary arterial pressure (PAP). Different stimulations varying in intensities were used, in rats nervously intact (IR-rats), after vagotomy (XT-rats), after chemodenervation obtained without vagotomy (CDN not XT-rats) or with XT (CDN + XT) and finally after alpha 1-receptors blockade (P-rats = pretreated rats). The observed variations were analysed in view of disentangling reflex part of PCS from a direct activity on the pulmonary vascular bed. Ventilation, PAP and systemic blood pressure (BP) were studied in anaesthetized rats. N2 test, NaCN test, 20 s of 5% O2 inhalation and almitrine bismesylate (ALM) were used as PCS, ranged in the order of their relative intensities, from the ventilatory responses observed in IR-rats. In IR-rats, N2-and CN test produced a similar transient increase of PAP, slightly more extended than the hyperventilation. After XT, the responses were prolonged, but amplified only in CN test. Ventilatory responses disappear after CDN, but as far as pulmonary hypertension is concerned, CDN + XT is more potent than CDN without XT to reduce or even suppress them. This fact is particularly evident with ALM who is the strongest PCS used. Similar reduction of PAP rise was also produced in P-rats in which ventilatory responses remain unchanged. Prolonged hypoxic inhalation induced a progressive fall of systolic BP and of PAP. The return to normal air breathing is followed by BP restoration and a long-lasting PAP increase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Social status,social context,and arterial blood pressure

As social change and economic development have proceeded, the prevalence of chronic diseases, especially cardiovascular diseases, has increased in the developing world. In part this is due to the adoption of diets and other health behaviors characteristic of industrialized nations; in part it is a function of changing social and economic circumstances. In this paper, we describe the development and testing of a model designed to account for social and economic effects on cardiovascular disease risk. The model incorporates the fact that global economic processes have made a lifestyle characterized by the consumption of Euroamerican material goods and information a basis for the assignment of social status in local communities. But economic change at the local level is rarely sufficient to provide a foundation for individuals' status aspirations. Hence, many individuals attempt to maintain a lifestyle inconsistent with their economic standing, a variable we term lifestyle incongruity. Here we describe how this factor is associated with higher blood pressure in a variety of settings and also how the effects of lifestyle incongruity can be modified in local contexts by social class and social role processes. This latter process, contextual modification, is illustrated by data from American Samoa. In this example, the association of lifestyle incongruity with blood pressure is examined in 30 male household heads and 26 spouses. After an examination of Samoan ethnography focused attention on the importance of age and gender differences as defining social contexts of intracultural variation, the model was modified to assess interactions between age and gender as they affect the association of lifestyle incongruity and blood pressure. Lifestyle incongruity is strongly associated with higher systolic and diastolic blood pressure for the younger household heads, minimally associated with blood pressure for older household heads, and only slightly associated with the blood pressure of their spouses. The regression coefficients for the lifestyle incongruity by age by sex interaction term was significant at P ≤ 0.01 for both systolic and diastolic blood pressure. The consistency of these results with expectations based on the ethnographic record is emphasized in the interpretation. We feel that the lifestyle incongruity model represents an empirically successful attempt to link global political-economic processes, local social structure, and biological outcomes. Am J Phys Anthropol 102:55–66, 1997. © 1997 Wiley-Liss, Inc.     

Transient interactions between blood pressure,respiration and heart rate in man

Auto regressive spectral estimation techniques have been used to follow transient interactions between mean blood pressure, respiration and heart rate. This demonstrates that these inter-relationships are variable. It is concluded that while central modulation of heart rate is the major factor in the interactions, when the heart rate is fixed, peripheral modulation of the blood pressure by respiration is clearly demonstrated.     

The effect of electrical stimulation of vestibular-complex formations on systemic arterial pressure and regional blood flow

Electrical stimulation of the descending and medial vestibular nuclei produced increased arterial blood pressure and also changes in regional blood flow. On stimulation of the descending vestibular nucleus there was a decrease in blood flow in the hind-limb muscles, which might be a response to stimulation of the ventrolateral parts of the nucleus; when the central parts of the nucleus were stimulated the blood flow decreased both in the hind-limb muscles and in some of the viscera. Stimulation of the medial vestibular nucleus, particularly its ventral parts, caused a decrease in blood flow in the skin of the hind limbs, often accompanied by a decrease in visceral blood flow. On the basis of analysis of the afferent and efferent connections of the descending and medial vestibular nuclei, it is suggested that the cerebellum takes part in the transmission of vasomotor influences.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 2, No. 1, pp. 35–42, January–February, 1970.