Pathways

Betaxolol is a competitive cardioselective beta 1 blocker. It can be administered orally, where it passes through hepatic portal circulation, and enters the bloodstream and travels to act on cardiomyocytes. In bronchial and vascular smooth muscle, betaxolol can compete with epinephrine for beta-2 adrenergic receptors. By competing with catecholamines for adrenergic receptors, it inhibits sympathetic stimulation of the heart. The reduction of neurotransmitters binding to beta receptor proteins in the heart inhibits adenylate cyclase type 1. Because adenylate cyclase type 1 typically activates cAMP synthesis, which in turn activates PKA production, which then activates SRC and nitric oxide synthase, its inhibition causes the inhibition of cAMP, PKA, SRC and nitric oxide synthase signaling. Following this chain of reactions, we see that the inhibition of nitric oxide synthase reduces nitric oxide production outside the cell which results in vasoconstriction. On a different end of this reaction chain, the inhibition of SRC in essence causes the activation of Caspase 3 and Caspase 9. This Caspase cascade leads to cell apoptosis. The net result of all these reactions is a decreased sympathetic effect on cardiac cells, causing the heart rate to slow and arterial blood pressure to lower; thus, betaxolol administration and binding reduces resting heart rate, cardiac output, afterload, blood pressure and orthostatic hypotension. By prolonging diastolic time, it can prevent re-infarction. Clinically, it is used to increase atrioventricular block to treat supraventricular dysrhythmias. Betaxolol also reduce sympathetic activity and is used to treat hypertension, angina, migraine headaches, and hypertrophic subaortic stenosis.

Betazole, also known as ametazole and Histalog, is a histamine H2 agonist that causes an increase in gastric acid secretion. Betazole is commonly used to evaluate acid production. Betazole binds to the H2 receptor to enhance the G protein signaling cascade to increase gastric secretion into the lumen. Gastric acid digests protein and absorbs calcium, iron and vitamin B12. Gastric acidity may also interfere with medication bioavailability. Measuring gastric acid secretion is useful to manage diseases involving acid production such as gastroesophageal reflux disease.

Betazole, also known as ametazole and Histalog, is a histamine H2 agonist that causes an increase in gastric acid secretion. Clinically, it may be used in place of histamine to reduce off-target effects when stimulating gastric secretion. Betazole is commonly used to evaluate acid production (as a diagnostic or lab test). It binds to the H2 receptor to enhance the G protein-coupled receptor (GPCR) signaling cascade leading to increased acid secretion into the gastric lumen. Gastric acid digests protein and absorbs calcium, iron and vitamin B12. Gastric acidity may also interfere with medication bioavailability. Measuring gastric acid secretion is useful to manage diseases involving acid production such as gastroesophageal reflux disease.

Bethanechol is a muscarinic agonist used to treat postoperative and postpartum nonobstructive functional urinary retention and neurogenic atony of the bladder with retention. It can be found under the brand name Duvoid. Bethanechol is a synthetic ester that was initially synthesized in 1935. As a cholinergic agent, bethanechol is similar in structure and pharmacological function to acetylcholine and is used in specific cases when stimulation of the parasympathetic nervous system is necessary. For example, bethanechol is readily used to treat postoperative or postpartum urinary retention. An advantage of bethanechol is that in contrast to acetylcholine, bethanechol is not degraded by cholinesterase allowing its effects to be longer-lasting. When taken orally or administered by injection, Bethanechol binds to and activates these muscarinic receptors. By doing so, it mimics the effects of acetylcholine, a neurotransmitter that naturally activates these receptors. The activation of M2 and M3 receptors leads to several physiological responses, including increased smooth muscle tone and contraction. Bethanechol is commonly used to stimulate bladder contractions in individuals with urinary retention or certain bladder disorders. By activating the M3 receptors in the bladder, it increases the tone of the detrusor muscle and causes the bladder to contract, thereby promoting urination. In addition to its effects on the urinary system, Bethanechol can also affect smooth muscles in other organs, such as the gastrointestinal tract. It can increase the muscular contractions of the gastrointestinal tract, which may be beneficial in certain conditions involving reduced motility, such as postoperative ileus or constipation. Possible side effects of using bethanechol may include belching, blurred vision, dizziness, and headache.

Bethanechol is a drug that is not metabolized by the human body as determined by current research and biotransformer analysis. Bethanechol passes through the liver and is then excreted from the body mainly through the kidney.

Bethanidine is a drug that is not metabolized by the human body as determined by current research and biotransformer analysis. Bethanidine passes through the liver and is then excreted from the body mainly through the kidney.