AT receptor blocker

High levels of circulating angiotensin II will stimulate the AT2-receptor and this mechanism may counteract the noxious process of vascular and myocardial remodeling. A potential theoretical advantage of the AT-receptor blockers over the ACE-inhibitors may be the inhibition of all Ang II effects at the AT-receptor level. ACE-inhibitors suppress a major portion of the Ang II synthesis, but the... 

Angiotensin AT receptor-blockers such as losartan (see Chapters 11 and 17) appear to have similar but more limited beneficial effects. Angiotensin receptor blockers should be considered in patients intolerant of ACE inhibitors because of incessant cough. In some trials, candesartan was beneficial when added to an ACE inhibitor. 

The angiotensin II AT receptor blockers (ARBs, eg, losartan) produce beneficial hemodynamic effects similar to those of ACE inhibitors. 

Hypertension. The antihypertensive effect of ACE inhibitors and AT receptor blockers results primarily from vasodilatation (reduction of peripheral resistance) with little change in cardiac output or rate renal blood flow may increase (desirable). A fall in aldosterone production may also contribute to the blood pressure lowering action of ACE inhibitors. Both classes slow progression of glomerulopathy. Whether the long-term benefit of these drugs in hypertension exceeds that to be expected from blood pressure reduction alone remains controversial. 

ACE inhibitors and AT -receptor blockers are most useful in hypertension when the raised blood pressure results from excess renin production (e.g. renovascular hypertension), or where concurrent use of another drug (diuretic or calcium blocker) renders the blood pressure renin-dependent. The fall in blood pressure can be rapid, especially with short-acting ACE inhibitors, and low initial doses of these should be used in patients at risk those with impaired renal function, or suspected cerebrovascular disease. These patients may be advised to omit any concurrent diuretic treatment for a few days before the first dose. The antihypertensive effect increases progressively over weeks with continued adminis-... 

The cautions hsted for the use of ACE inhibitors (above) apply also to AT receptor blockers. 

Figure 11-4. Actions of angiotensin-converting enzyme inhibitors and AT receptor blockers. The enzyme is responsible for activating angiotensin by conversion of angiotensin I to angiotensin II and for inactivating bradykinin, a vasodilator normally present in very low concentrations. Block of the enzyme thus decreases the concentration of a vasoconstrictor and increases the concentration of a vasodilator. The AT, receptor antagonists lack the effect on bradykinin levels, which may explain the lower incidence of cough observed with these agents.

Discuss the differences between ACE inhibitors and AT -receptor blockers in the context of the peptides described in this chapter. The Skill Keeper Answer appears at the end of the chapter. 

Losartan Angiotensin AT, receptor blocker prototype used in HTN. Effects and toxic-... 

Microvascular injury Angiotensin II (AT) receptor blockers, contrast agent (iopamidol), sorafenib... 

Figure 8. Simultaneous measurement of intracellular Ca and oxidant production in neutrophils. Cells were labeled with Quin-2 and suspended at 2 x lo cells/mL buffer. At time zero, 1 nJf FLPEP was added (upper trace in each panel). In addition, the receptor blocker tBOC was added (3 x 10" M) after 30 s to stop further binding of the stimulus (lower trace in each panel). The excitation wavelength was 3A0 nm. Top panel Quin-2 fluorescence determined on channel B (of Figure 1) using a Corion A90-nm interference filter. The crossover from the superoxide assay has been subtracted. Middle panel Oxidant production (superoxide equivalents) determined by the para-hydroxyphenylacetate assay. Fluorescence was observed at AOO nm (on channel A of Figure 1).

In general, early pharmacotherapy of NSTE ACS (Fig. 5-3) is similar to that of STE ACS with three exceptions (1) fibrinolytic therapy is not administered (2) glycoprotein Ilb/IIIa receptor blockers are administered to high-risk patients for medical therapy as well as to PCI patients and (3) at this time, there are no standard quality indicators for patients with NSTE ACS who are not diagnosed with MI. 

Glycoprotein llb/llla receptor blockers Bleeding, acute profound thrombocytopenia Clinical signs of bleeding3 baseline CBC and platelet count daily CBC platelet count at 4 hours after initiation then daily... 

Initial evidence linking Hebb s coincidence detection rule to learning and memory. As the unique receptor in the brain with the coincidence-detection property, the NMDA receptor is an ideal candidate to gate the formation of memory at the synaptic level. Early observations demonstrated that infusion of NMDA receptor blockers into brain ventricles resulted in animals poor performance in the hidden-platform water maze. At first, this seemed to provide evidence for the role of hippocampal LTP in memory formation. Unfortunately, careful analyses revealed that poor performances in the water maze tests... 

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