Browsing Pathways

Phenindione is a medication that is used as an anticoagulant. Anticoagulants are drugs that prevent the blood from coagulating and creating blood clots. It is used to treat a variety of conditions, including cerebral and pulmonary embolisms, as well as cardiomyopathy. Phenindione works by thinning the blood, which is done through the antagonization of vitamin K. This antagonization is needed to create the factors that cause clotting in the liver. Phenindione resembles warfarin action-wise, but warfarin is preferentially used as there have been more instances in hypersensitivity in phenindione patients.

Dicoumarol (also known as bishydroxycoumarin) is an anticoagulant that inhibit the liver enzyme vitamin K reductase, which cause Vitamin K1 2,3-epoxide could not be catalyzed by vitamin K reductase to form vitamin KH2, the reduced form of vitamin K. Vitamin K-dependent coagulation factors (II, VII, IX, and X) requires its cofactor, vitamin K to facilitate the activation and gamma-carboxylation. Inhibition of vitamin K reductase results in reduced concentration of vitamin KH2, which will ultimately lead to decreased coagulability of the blood and reduced cleavage of fibrinogen into fibrin.

Bopindolol (also known as Sandonorm) is a selective β1 adrenergic receptor antagonist (beta blocker), which can be used for treatment of high blood pressure (hypertension) and irregular heartbeats (arrhythmias). Bopindolol also has the ability to mild intrinsic sympathomimetic activity (ISA) with effective range of dosage. Adrenaline (also known as epinephrine) can activate β1 adrenergic receptor so that the heart rate and output will be increased. Renin is a hormone that generated from kidney, which could lead to constriction of blood vessels. Beta blockers could efficiently prohibit renin release.

Carteolol (also known as Cartrol or Ocupress) is a selective β1 adrenergic receptor antagonist (beta blocker), which can be used for treatment of high blood pressure (hypertension) and irregular heartbeats (arrhythmias). Carteolol also has the ability to mild intrinsic sympathomimetic activity (ISA) with effective range of dosage. Adrenaline (also known as epinephrine) can activate β1 adrenergic receptor so that the heart rate and output will be increased. Renin is a hormone that generated from kidney, which could lead to constriction of blood vessels. Beta blockers could efficiently prohibit renin release.

Timolol is a beta blocker medication, making it part of the antihypertensive drug class. It relieves symptoms such as tachycardia, vascular headaches, hypertension, angina and tremors. Timolol, much like propranolol or oxprenolol, begins its journey by inhibiting the beta-1 adrenergic receptors in the heart. Entering the myocyte, this activates a G-protein signalling cascade, which activates cAMP -dependent protein kinase type 1-alpha regulatory subunit. From there, cAMP-dependent protein kinase catalytic subunit alpha activates outage-dependent L-type calcium channel subunit alpha 1C and 2 other transports which bring calcium into the myocyte from outside of the cell. cAMP-dependent protein kinase catalytic subunit alpha is activated through ryanodine receptor 2, which is also transporting calcium into the myocyte from the the sarcoplasmic reticulum. The calcium and calmodulin then activate myosin light chain kinase, which is located in the smooth vascular muscle. This, paired with the calcium activating a series of troponin enzymes that activate tropomyosin enzymes in the striated muscle, results in a muscle contraction. Then in the cell membrane we have PIP2(16:0/20:3(8Z,11Z,14Z)) catalyzing into DG(14:0/14:1(9Z)/0:0) and inositol 1,4,5-triphosphate with the help of the enzyme 1-phosphatidylinositol 4,5-biphosphate phosphodiesterase beta-1. This enzyme is activated through the G-protein signalling cascade, which stems from the type-1 angiotensin II receptor. Around the cell there are many transports happening through many different transporters, leading in and out of the cell Some of the transports into the cell include sodium and calcium, while transports are also working hard to constantly export potassium from the cell. Returning to the sarcoplasmic reticulum, cardiac phospholamban inhibits the transporter sarcoplasmic/endoplasmic reticulum calcium ATPase 2, which sees water and ATP catalyzed through it to become phosphorus and ADP, while transporting calcium into the sarcoplasmic reticulum.

Sotalol is a beta-adrenergic receptor antagonist, which is a treatment regimen for heart failure such as abnormal heart rhythms. Sotalol inhibits response to adrenergic stimuli by competitively blocking β1-adrenergic receptors within the myocardium and β2-adrenergic receptors within bronchial and vascular smooth muscle. The electrophysiologic effects of sotalol may be due to its selective inhibition of the rapidly activating component of the potassium channel involved in the repolarization of cardiac cells.

Epinephrine can be derived from phenylalanine and tyrosine and it is an active sympathomimetic hormone that can be secreted from adrenal medulla. Epinephrine can stimulate alpha- and beta- adrenergic systems by binding on alpha-1 and beta-1 adrenergic receptors to make gastrointestinal relaxation, stimulates the heart, etc. Epinephrine can also be used to delay absorption of local anesthetics, constrict arterioles in skin and gut while dilating arterioles in leg muscles, increase glycogen hydrolysis to glucose in liver to raise up blood sugar level and breaking down lipids in adipocytes. Epinephrine can also play role as suppressive agent in immune system.

Dobutamine is a type of medication that can be used for treating heart failure and cardiogenic shock. Dobutamine can bind to beta-1 adrenergic receptor on the heart cell which lead to mild chronotropic, arrhythmogenic, hypertensive and vasodilative effects. Dobutamine can also bind to beta-2 or alpha receptors. For patients with cardiac decompensation, dobutamine is required for inotropic support.

Isoprenaline (also known as isoproterenol) is a selective beta adrenergic bronchodilator that can be used for treating slow heart rate (bradycardia), heart block, and rarely for asthma. Isoprenaline can bind and inhibit beta-1 adrenergic receptor on both vascular smooth muscle, which lead to inhibition of vasoconstriction in peripheral blood vessels and adrenergic stimulation of endothelial cell function.

Arbutamine is a synthetic catecholamine used to initiate a cardiac stress response to mimic exercise to detect coronary artery disease. Arbutamine has nonselective beta and weak alpha-1-adrenergic activity which causes increased chronotropic activity (increase in heart rate) and inotropic activity (increase myocardial contractility). These effects mimic the cardiovascular effects of exercise. For patients with cardiovascular artery disease, arbutamine can induce myocardial ischemia. Arbutamine is delivered via a computer controlled closed-loop system. The infusion of arbutamine is based off the heart rate feedback. The system monitors heart rate and blood pressure throughout infusion with alarms for physiological changes or problems.