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At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Marihuana and the cardiovascular system.

The actions of marihuana on the cardiovascular system in man are the most consistent physiological effects produced by acue administration. Significant tachycardia and conjunctival injection are well established effects. When the subject is upright, marihuana produces a fall in blood pressure; however, either no significant effect or a slight increase in blood pressure occurs when the subject is supine. Marihuana has been reported to increase limb blood flow and produce no significant effect on electrocardiogram of normal subjects. It, however, interferes with the integrity of peripheral vascular reflex responses. Although the detailed mechanism of action has not been elucidated, there is evidence that marihuana produces both sympathetci nervous system stimulation and parasympathetic nervous system blockade. No data are available that indicate the acute administration of marihuana presents a significant hazard to the cardiovascular system of normal subjects.

Animals↗
PubMed1999

[The effect of prolonged physical loads on the cardiovascular system of middle-school-aged pupils].

The cardiovascular system of schoolchildren at the age of 11-15 was studied as affected by systemic of long lasting physical loads of schoolchildren. In the trained children contrary to adults the respiratory arrhythmia is observed, that evidences for nonadequacy of the physical load to the functional state of myocardium. In the cardiovascular system of the trained schoolchildren under the effect of constant training there occurs a series of functional changes which increase adaptation to physical loads, that is manifested in a decrease of the systolic and diastolic pressure, the lowering of the systolic index and heart rate, and in increase in mechanical and electromechanical systoles, the amplitude of the teeth R and T. The detected changes in the cardiovascular system are due to the value of trained loads and their nonadequacy to the functional state of myocardium.

Adaptation, Physiological↗
PubMed1983

[Intensity of kininergic reactions of the cardiovascular system in different activities of the plasma kallikrein-kinin system].

The reactions of cardiovascular system at various intensities of kininogenesis were studied with the aid od dose--effect curves of bradykinin hypotensive action. Correlations were found between the intensity of kinin--induced reaction and the level of some components of the blood Kallikrein-kinin system. Activation of kininogenesis was accompanied by a decrease of kinin-reactivity whereas inhibiton of kinin formation was followed by an augmentation of the hypotensive kinin-induced reaction.

Animals↗
PubMed2006

[Preoperative stratification of risks in patients with disorders of the cardiovascular system].

Disorders of the cardiovascular system are among the most important accompanying diseases in operative medicine. These diseases increase the perioperative risk; the risk is assessed on the basis of the case history and tolerance of the patient as well as the extent and invasiveness of the surgical intervention. Depending on the results of this stratification further examination and therapy may be necessary. The aim of these mainly preventative measures is the highest possible preoperative hemodynamic stability. Besides pharmacological prevention, a therapy for hypertension or ischemia belongs among these measures. The selected anesthesia process must guarantee and efficient prevention of pain.

Anesthesia↗
PubMed2005

The peripheral-type benzodiazepine receptor and the cardiovascular system. Implications for drug development.

Peripheral-type benzodiazepine receptors (PBRs) are abundant in the cardiovascular system. In the cardiovascular lumen, PBRs are present in platelets, erythrocytes, lymphocytes, and mononuclear cells. In the walls of the cardiovascular system, PBR can be found in the endothelium, the striated cardiac muscle, the vascular smooth muscles, and the mast cells. The subcellular location of PBR is primarily in mitochondria. The PBR complex includes the isoquinoline binding protein (IBP), voltage-dependent anion channel (VDAC), and adenine nucleotide transporter (ANT). Putative endogenous ligands for PBR include protoporphyrin IX, diazepam binding inhibitor (DBI), triakontatetraneuropeptide (TTN), and phospholipase A2 (PLA2). Classical synthetic ligands for PBR are the isoquinoline 1-(2-chlorophenyl)-N-methyl-N-(1-methyl-propyl)-3-isoquinolinecarboxamide (PK 11195) and the benzodiazepine 7-chloro-5-(4-chlorophenyl)-1,3-dihydro-1-methyl-2H-1,4-benzodiazepin-2-one (Ro5 4864). Novel PBR ligands include N,N-di-n-hexyl 2-(4-fluorophenyl)indole-3-acetamide (FGIN-1-27) and 7-chloro-N,N,5-trimethyl-4-oxo-3-phenyl-3,5-dihydro-4H-pyridazino[4,5-b]indole-1-acetamide (SSR180575), both possessing steroidogenic properties, but while FGIN-1-27 is pro-apoptotic, SSR180575 is anti-apoptotic. Putative PBR functions include regulation of steroidogenesis, apoptosis, cell proliferation, the mitochondrial membrane potential, the mitochondrial respiratory chain, voltage-dependent calcium channels, responses to stress, and microglial activation. PBRs in blood vessel walls appear to take part in responses to trauma such as ischemia. The irreversible PBR antagonist, SSR180575, was found to reduce damage correlated with ischemia. Stress, anxiety disorders, and neurological disorders, as well as their treatment, can affect PBR levels in blood cells. PBRs in blood cells appear to play roles in several aspects of the immune response, such as phagocytosis and the secretion of interleukin-2, interleukin-3, and immunoglobulin A (IgA). Thus, alterations in PBR density in blood cells may have immunological consequences in the affected person. In conclusion, PBR in the cardiovascular system may represent a new target for drug development.

Animals↗
PubMed2002

Circadian rhythm in the cardiovascular system: considerations in non-invasive electrophysiology.

Most cardiovascular activities show a circadian rhythm, as do electrophysiological phenomenon. Under the influence of both external stimuli and endogenous homoeostatic mechanisms, cardiac electrophysiological properties change diurnally and enable the cardiovascular system adapt to rest-exercise cycles. According to recent reports, almost all non-invasive electrophysiological phenomena, such as electrocardiographic indices, cardiac refractoriness and conduction, pacing and defibrillation threshold, heart rate variability indices, and even Q-T dispersion and T-wave alternans, show diurnal variability. Furthermore, many of these changes are clinically significant and may affect results of some diagnostic studies. These characteristics of the cardiovascular system require us keep in mind the "time" factor any time we analyze electrophysiological results and make clinical decisions.

Arrhythmias, Cardiac↗
PubMed2001

Similitude in the cardiovascular system of mammals.

Scaling laws governing the cardiovascular system of mammals are discussed in the present review in a manner emphasizing their experimental basis. Specific attention is given to the well-known experimental laws requiring the rate of oxygen consumption and the heart rate of mammals to vary with body mass raised to the powers 3/4 and -1/4, respectively. This review involves reconsideration and further discussion of the previous work of the writer in which these and other scaling relationships were developed from fundamental considerations. The predicted scaling laws remain unchanged from the earlier work, but alternative assumptions leading to the laws are used so as to provide additional insight. The scaling laws are shown to have their origin in the basic design of the cardiovascular system and in the basic processes involved in its working. Modification of the design assumptions of the system to account for known differences in the relative heart masses of mammals and birds is shown to lead to the scaling laws for rate of oxygen consumption and heart rate of birds.

Animals↗
PubMed1998

Cortical modulation of the cardiovascular system.

Cortical modulation of central cardiovascular control mechanisms has been recognized for many decades. However, it is only recently that the mechanisms underlying cortical influences on circulatory function have been systematically examined. This review considers the view that certain regions of the cerebral cortex, including the medial prefrontal cortex (MPFC) and insular cortex (IC), participate in specific aspects of central circulatory control. Anatomical investigations indicate that these cortical areas are connected with hypothalamic, midbrain, pontine and medullary brain regions involved in cardiovascular control. Lesions of the MPFC and IC have demonstrated modulation of the activity of cardiovascular reflexes such as the baroreceptor heart rate reflex and involvement in conditioned cardiovascular responses. Electrophysiological studies have provided evidence that cortical regions are able to influence premotor sympathoexcitatory vasomotor neurons within the rostral ventrolateral medulla and subsequently alter sympathetic vasomotor tone. Cortical regions such as the IC receive visceral sensory information arising from baroreceptors and chemoreceptors within the cardiovascular system. In contrast, the MPFC receives afferents predominantly from limbic sources, although its outputs include structures associated with central sympathetic vasomotor control. Cortical modulation of circulatory function has been demonstrated in man and may underlie the cardiovascular components of a number of conditions. It is suggested that cortical areas involved in visceral sensory or visceral motor processes associated with circulatory function may be involved in generation of patterns of cardiovascular responses specific for certain behaviours.

Afferent Pathways↗
PubMed1992

The effect of oestrogen on the female cardiovascular system.

OBJECTIVE: To review the present state of knowledge regarding the effect of oestrogen on the female cardiovascular system (e.g. atherosclerosis, myocardial infarction, hypertension and thrombosis). DATA SOURCES: Over 100 articles (most published over the last 10 years) were reviewed. They included epidemiological, biochemical, physiological, animal and clinical studies which related to the effect oestrogens have on the cardiovascular system of postmenopausal women. These data contained a wide cross-section of results and outcomes and each study was summarised to provide the most relevant information. Where a particular study provided an opinion or result at variance with the majority opinion, that study has been discussed in greater detail. STUDY SELECTION: All published papers which appeared to be relevant to an understanding of the clinical implications of oestrogen replacement therapy and its impact on the female cardiovascular system were included in this analysis. Some papers which appeared to repeat data and results previously published were not included. DATA SYNTHESIS: The overwhelming eight of evidence from this literature review supports the concept that oestrogen reduces the risk of atherosclerosis and myocardial infarction. It also confirms that postmenopausal "natural" oestrogen is a vasodilating agent which will lead to a fall in blood pressure and an improvement in blood flow and the pulsatility index. Although oral oestrogen did appear to increase thrombogenic activity, there was no clinical evidence that "natural" oestrogen taken after the menopause increased the risk of venous thrombosis. CONCLUSIONS: The consensus of the published data is that oestrogen conveys a highly protective effect on the cardiovascular system of postmenopausal women. There will be a reduction of up to 50% in myocardial infarction and stroke, a reduction in the incidence of hypertension and an improvement in blood flow. Some of the data suggest that even for women who have suffered from an infarct, their long-term survival is enhanced by oestrogen therapy. The medical myth that oestrogen has a deleterious effect on the cardiovascular system of women is finally laid to rest.

Aged↗
PubMedDate not supplied

[Somatostatin as a regulator of cardiovascular system functions].

The control of cardiovascular system is provided not only by regulatory influence of classical neurotransmitters, acetylcholine and noradrenaline, but also some regulatory peptides have very important physiological significance. One of them is somatostatin, a peptide which possess pronounced cardiotropic activity. Somatostatin-like immunoreactivity was found in the heart of several mammals including man; it was detected in the atrial and ventricular myocardium, conductive system of the heart and cardiac postganglionic parasympathetic neurons. Somatostatin co-exists with acetylcholine in presynaptic vagal endings and may be released by high-frequency stimulation of the vagus nerve. The main cardiac effects of somatostatin are heart rate deceleration, decrease of myocardial contractility and slowing of propagation velocity along conductive system of the heart. Somatostatin plays role in cardiac rhythmogenesis. It modifies electrophysiological properties of cardiac pacemaker, modulates cardiac chronotropic action of autonomic nervous system and prevents supraventricular tachyarrhythmias. Somatostatin diminish cardiac output and affects blood pressure level; the character of vascular effects evoked by this peptide may be different in various species of animals. Somatostatin increases peripheral vascular resistance and provokes a decrease of regional blood flow, especially in mesenterial and hepatoportal vessels. This effect is great of clinical importance in case of gastroduodenal and oesophageal bleedings. Cardiovascular effects of somatostatin may result from its modulatory action on presynaptic release of acetylcholine, noradrenaline and other humoral substances. On the other hand, some effects of somatostatin result from its transmitter action which is provided by interaction of somatostatin with own receptors. Somatostatin receptors are coupled with adenylate cyclase activity and ion channels through inhibitory G-proteins. Excitation of somatostatin receptors causes a decrease of intracellular cAMP content, inhibition of inward calcium current and activation of potassium membrane conductance. There exist five different subtypes of somatostatin receptors which have different structure, pharmacological properties and distribution in various tissues. The data presented in this review make it possible to conclude that cardiovascular effects of somatostatin are very important part in the spectrum of physiological activity of this peptide.

Animals↗
PubMedDate not supplied

[Morphofunctional changes in the cardiovascular system in nitroglycerin poisoning].

The cardiovascular system was examined in acute, subacute and chronic intoxications with nitroglycerin. It was revealed that morphofunctional alterations were uniform in nature, being more demonstrable in chronic exposure during 6 months. Myocardial alterations were characterized by disturbed hemodynamics, dystrophy, focal myocarditis, changes in the activity of enzymes, and changes in the electrocardio- and rheovasographic readings. Prolonged intoxication produced more profound and stable alterations.

Animals↗
PubMedDate not supplied

Cardiovascular system in leprosy.

Involvement of cardiovascular system (CVS) in 50 multibacillary (MB) and 20 paucibacillary (PB) cases of leprosy was evaluated. 20 age and sex matched controls were also studied. In addition to detailed clinical examination and resting electro-cardiogram, Master's two step exercise test (DMT) was also carried out to find out the occult and asymptomatic cardiac involvement. We have not found any significant symptomatic or electrocardiographic evidence of CVS involvement in various groups of leprosy.

Adult↗
PubMed2001

A forward model-based validation of cardiovascular system identification.

We present a theoretical evaluation of a cardiovascular system identification method that we previously developed for the analysis of beat-to-beat fluctuations in noninvasively measured heart rate, arterial blood pressure, and instantaneous lung volume. The method provides a dynamical characterization of the important autonomic and mechanical mechanisms responsible for coupling the fluctuations (inverse modeling). To carry out the evaluation, we developed a computational model of the cardiovascular system capable of generating realistic beat-to-beat variability (forward modeling). We applied the method to data generated from the forward model and compared the resulting estimated dynamics with the actual dynamics of the forward model, which were either precisely known or easily determined. We found that the estimated dynamics corresponded to the actual dynamics and that this correspondence was robust to forward model uncertainty. We also demonstrated the sensitivity of the method in detecting small changes in parameters characterizing autonomic function in the forward model. These results provide confidence in the performance of the cardiovascular system identification method when applied to experimental data.

Autonomic Nervous System↗
PubMed1995

Endothelium-dependent regulation of the cardiovascular system.

Vascular endothelial cells play an important role in modulating cardiovascular function, by liberating several vasoactive substances, such as prostacyclin, endothelium-derived relaxing factor/nitric oxide, a hyperpolarizing substance, and vasoconstrictor substances. Their roles in the cardiovascular system include modulation of the contraction of the underlying vascular smooth muscle, interaction between blood components and blood vessel wall, vascular growth, as well as regulation of the cardiovascular system at several levels beyond the vascular wall. Alterations in the endothelial functions and the related processes are now known to be involved in the pathogenesis of many cardiovascular diseases, including hypertension and atherosclerosis. Thus, the impaired endothelial regulation of the cardiovascular system may have an important implication for the development and progression of many cardiovascular diseases.

Blood Circulation↗
PubMed1995

Hypothalamic and medullary GABAA and GABAB-ergic systems differently regulate sympathetic and cardiovascular systems.

1. To determine whether hypothalamic and medullary GABA (gamma-aminobutyric acid)B stimulation would affect the sympathetic and cardiovascular activities, and to determine whether these effects would be altered in hypertension, baclofen (a GABAB agonist) was injected into a hypothalamic pressor area (ventromedial hypothalamus, VMH), a depressor area (anterior hypothalamus, AH), or a nucleus tractus solitarius (NTS) in normotensive and spontaneously hypertensive rats (SHR). 2. Intracerebroventricular (ICV) injections of a GABAA agonist (muscimol, 1 mu g) decreased blood pressure (BP) and heart rate (HR). ICV injections of baclofen (2 mu g) elicited biphasic depressor and pressor effects, and these effects were abolished by a pretreatment with saclofen (GABAB antagonist, 100 mu g, icv). 3. Muscimol (400 ng) and baclofen (800 ng) injected into VMH decreased sympathetic nerve activity (SNA), BP and HR to almost similar levels, while saclofen injected into VMH increased HR without affecting BP levels. 4. The same dose of baclofen injected into AH increased BP, but muscimol (AH) did not alter BP. 5. Both muscimol and baclofen injected into NTS increased BP, but its magnitude was larger in baclofen injections. 6. Depressor and sympatho-inhibitory effects of baclofen (VMH) in SHR were larger than those in normotensive Wistar-Kyoto (WKY) rats, while pressor responses elicited by baclofen (AH) did not differ between SHR and WKY. 7. In summary, GABA reduces SNA, BP and HR through both GABAA and GABAB receptors in VMH. In addition, the GABAB system acts on AH and NTS to further regulate the cardiovascular activities. In SHR, GABAB-ergic dysfunction in VMH but not in AH might contribute to the development of hypertension.

Animals↗
PubMed1982

Arterial branching in various parts of the cardiovascular system.

Angiographic pictures of vascular beds in various parts of the cardiovascular system were analyzed to study the geometrical structure of arterial bifurcations. The sites of arterial bifurcations were enlarged individually, and measurements were made of the branching angles and branch diameters at each site. Results from various parts of the cardiovascular system of man, and some from rabbit and pig, were compared with each other. The measurements were also compared with "optimum" values of branching angles and branch diameters which have been predicted by various theoretical studies. In general the measurements were found to give support to the theoretical premise that branching angles and branch diameters in the cardiovascular system are dictated by certain optimality principles which aim to maximize the efficiency of the system in its fluid-conducting function. In some parts of the system, however, the measured angles and diameters were found to be decidedly lower than those predicted by theory.

Animals↗
PubMed1983

Effect of photochemotherapy on the cardiovascular system.

The effect of PUVA therapy on the cardiovascular system was studied in 2 groups of patients. The first group consisted of 9 otherwise healthy patients, who were treated without airconditioning. The second group was formed by 15 otherwise healthy psoriasis patients, who were treated with photochemotherapy, using airconditioning. In both groups the cabinet-skin and rectal temperature rose significantly. The most marked finding however was the rise in heart rate. By applying airconditioning, significantly smaller increases in the measured parameters occurred. In none of the patients changes in the electrocardiograms were observed. The effects on the cardiovascular system can evidently be limited by applying airconditioning and by keeping the time of light exposure as short as possible.

Adult↗