While a plant-based meal would qualify as vegan (adjective), a person who follows a plant-based (vegan) diet is not necessarily a vegan (noun). For example, someone could follow a plant-based diet but still wear leather and have no moral issue with hunting or killing animals for food.
Ball-and-stick model of cimetidine, the prototypical H 2 -receptor antagonist. The H2 receptor antagonists are a class of drugs used to block the action of histamine on parietal cells (specifically the histamine H2 receptors) in the stomach, decreasing the production of acid by these cells.he H 2 antagonists are competitive antagonists of histamine at the parietal cell H 2 receptor. They suppress the normal secretion of acid by parietal cells and the meal-stimulated secretion of acid.
A receptor antagonist is a type of receptor ligand or drug that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it like an agonist. They are sometimes called blockers; examples include alpha blockers, beta blockers, and calcium channel blockers. In pharmacology, antagonists have affinity but no efficacy for their cognate receptors, and binding will disrupt the interaction and inhibit the function of an agonist or inverse agonist at receptors.