Cardiovascular system structure

A variety of responses in the body to different adrenergic drugs are based on their relative selectivity when binding with various receptors, which are exclusively found in and unevenly distributed in effector structures (heart, cardiovascular system, lungs, brain, peripheral nervous system, etc.). 

The a for structural development of serotonin (simple indole alkaloid) is L-tryptophan, and the j3 is 5-hydroxy-L-tryptophan (Figure 64). Serotonin is a monoamine. It is a hioactive alkaloid known as a neurotransmitter. It has been found in the cardiovascular system, in Wood cells and the peripheral and CNS. 

LAs block nerve conduction when applied locally to nervous tissue by a voltage- and frequency-dependent inhibition of sodium currents (see Voltage-gated Sodium Channels Structure and Function1). Due to this mechanism, they preferentially block hyperexcitable cells and interfere comparatively less with normal physiological sensory and motor function. However, they are not selective for pain-relevant sodium channel subtypes so that they have a relatively high risk of adverse effects associated with the central nervous and cardiovascular systems when administered systemically. Known LAs are not active when administered orally. 

O Malley KL, Harmon S, Tang L, Todd RD (1992) The rat dopamine D4 receptor sequence, gene structure and demonstration of expression in the cardiovascular system. New Biol 4 137-146. 

This drug has some similarities in its chemical structure to isoniazid but acts in a completely different way. It is used to treat high blood pressure which it does by dilating blood vessels. This means that there is less resistance to the blood flowing through the small vessels, the capillaries, and so the pressure in the blood system (cardiovascular system) is lower. 

Side Effects a.nd Toxicity. Adverse effects to the tricyclic antidepressants, primarily the result of the actions of these compounds on either the autonomic, cardiovascular, or central nervous systems, are summarized in Table 3. The most serious side effects of the tricyclics concern the cardiovascular system. Arrhythmias, which are dose-dependent and rarely occur at therapeutic plasma levels, can be life-threatening. In order to prevent adverse effects, as well as to be certain that the patient has taken enough drug to be effective, the steady-state semm levels of tricyclic antidepressant dmgs are monitored as a matter of good practice. A comprehensive review of structure—activity relationships among the tricyclic antidepressants is available (42). 

Adrenergic receptors (ARs) are the interface between the sympathetic nervous system and the cardiovascular system. ARs include two major subtypes, a and P, based on their pharmacological properties and molecular structure. The a-ARs consist of three ar AR subtypes and three o -ARs. P-ARs are also classified into three well-characterized subtypes Pb p2, and P3. Although they respond to the same hormones (norepinephrine and epinephrine), a- and P-ARs differ significantly in the types of cellular responses they mediate. 

Thyroid hormone has multiple effects on the cardiovascular system with various physiological consequences. Several genes that encode important regulatory and structural proteins in the heart have been shown to be thyroid hormone responsive. Thyroid hormone increases cardiac contractility, induces vasorelaxation and angiogenesis, prevents fibrosis and has favorable effects on lipid metabolism (reviewed by Pantos73). 

Many diseases result from the dysfunction of cells located outside the cardiovascular system. Thus, for a drug to exert its therapeutic effects, it must exit from the central circulation and interact with its extravascular-extraceUular or extravascular-intracellular target(s). This process of transvascular exchange is called extravasation, and it is governed by the permeability of blood capillary walls. The main biological features that control permeability of capillaries include the structure of the capillary wall under normal... 

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