Heart activation

The most difflcult pharmaceutically relevant oxidation of steroids is the introduction of a 14 -hydroxyl group. This functional group is found in heart-active steroids (cardenolides) such as digitoxigenin, which also contain a 17/J-butenolide substituent. The 14/ -hydroxyl group is easily cleaved off by dehydration and must therefore not be treated with Lewis or... 

Armepavine (6,7-dimethoxy-4 -hydroxy-l-benzyltetrahydroisoquino-line) was isolated for the first time by Konovalova et al. (377) from Papaver armeniacum (L.) DC. Administration of armepavine to white mice, rabbits, and cats causes irritation and tonicoclonic convulsions (378) and disorders in heart activity. It has no spasmolytic, para-sympathicolytic, or anesthetic properties. 

Thus far the pharmacologically investigated alkaloids of this group (protopine, cryptopine, and a-allocryptopine) affect the heart activity. They are active dilators of the coronary vessels (573). After i.v. administration to rabbits and guinea pigs, a slight increase in blood pressure and a greater tendency to the development of cardiac arrhythmia induced by epinephrine are observed. 

Gotsev T. 1944. [Blood pressure and heart activity III. Action of barium on the circulation]. Arch Exp Pathol Pharmakol 203 564-577. (German)... 

Razeghi P, Volpini K, et al. 2007. Mechanical unloading of the heart activates the calpain system. J Mol Cell Cardiol 42 449-452. 

The sympathetic nervous system plays a central role in regulating heart function and response to most types of stress through p-AR stimulation. Binding of p-adrenergic agonists to receptors in the heart activates adenylyl cyclase (AC) via a stimulatory G protein. On the other hand, it is known that the altered responses of the... 

Atrial natriuretic peptide (= ANP Atrial natriuretic factor ANF)] (protein) Animals ex stressed heart Activates PM GC (ANPR-A ANPR-B) - via NPR-A NPR-B (guanylyl cyclase-coupled receptors) induces plant stomatal opening inhibited by GC inhibitors LY83583 Methylene blue... 

Sodium is crucial for maintaining proper fluid balances in humans and animals. Sodium ions are responsible for signal transmission across nerve-cell membranes and in regulating heart activity and other metabolic functions. It is not as important in plant systems, however, and is even toxic to many plant species. This is the reason that a vegetarian diet can lower sodium levels in the blood, and explains why deer, horses, and other livestock need natural or synthesized salt licks for health. 

Calcium entry blockers reduce the frequency of anginal episodes and now play an important role in the management of patients prone to anginal episodes (Table 4.4). Beta-adrenergic blockers suppress heart activity, thus lowering the oxygen requirements of myocardial cells (Table 4.3C). 

The bufogenins responsible for the heart activity with positive inotropic effect, and the bufotoxins acting as convulsive toxins, need not be mentioned further in this context (ref.3) as they do not possess a remarkable growth inhibition effect on microorganisms. Research in this field, however, is still limited. 

Analeptics are substances which stimulate breathing and heart activity. Methyl-phenidate (Ritalin) is an analeptic often prescribed for children with Attention Deficit Hyperactivity Disorder (ADDHD). 

Heart activity Woven/knifled electrodes Electrical activity of heart Thoracic region... 

With an ideal current dipole in an infinite volume, zero potential will exist in all directions if the distance to the dipole is large enough. Unfortunately, an indifferent (neutral) ECG electrode does not exist because the human body is not large enough. If we go out in one direction along a limb, the limb proper is isoelectric with respect to the heart activity, but not with respect to other sources (e.g., respiration). If we go out along a second limb that too will be isoelectric however, the potential will not be equal to that of the first limb. Therefore none of them represents a true indifferent electrode. 

ECG (heart rate, heart rate variability, heart activity)... 

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