Receptors in Intestinal Muscles

Receptors in Intestinal MusclesThe experiment was conducted in order to wee-wee better understanding of the function of the sense organs in the guinea pig ileum. For this reason, divers(a) agonists and oppositions were used and the tendon reaction was monitored. The results of our experiment are summarized in the future(a) table.As we can see acetylcholine and hexamethonium twain have a triethylamine at one end and a straight chain of carbons. The basic unlikeness is that hexamethonium has cardinal tertiary amines, one on each end of the chain, whereas acetylcholine has the convocation -O-C(=O)-CH3 on one end. According to the SAR theory (Structure Activity Relationship) similar molecules in structure tend to have similar biological activity. As we know, both acetylcholine and hexamethonium hold in to the nicotinic receptor, the first one to trigger a receipt and the bet on one to prevent acetylcholine from binding. Hexamethonium, having two active groups, can probably bi nd more easily to the receptor, effectively blocking the acetylcholine action.b)Histamine and mepyramine have less similarities in structure. Both of them have three north and an aromatic ring. Histamine has the two nitrogen inside the aromatic ring whereas mepyramine has hardly one nitrogen bouncing in the ring. Both compounds bind to the H1-Histamine receptor, to trigger different reactions. The difference in structure can be explained by the different action of the two compounds. Histamine causes compressing of the massiveness and mepyramine causes its heartsease.The medicines tested were classified as agonists and antagonists.Acetylcholine Acts as neurotransmitter. It binds on the muscarinic and nicotinic receptors and causes muscle abridgment.Histamine Is also a neurotransmitter. It binds on the H1-Histamine receptor and causes smooth muscle contraction.Nicotine It acts on the nicotinic cholinergic receptors and mimics the neural transmission. It stimulates the muscle, then blocks stimulation.Isoprenaline Although isoprenaline was seeming(a)ly an antagonist, it is actually a selective agonist for the - adrenergic receptors that causes muscle relaxation. It is a sympathomimetic medicine that mimics the effect of stimulating the postganglionic adrenergic sympathetic nerves.Hexamethonium It is a nicotinic antagonist and a ganglionic blocker. It binds to the nicotinic cholinergic receptors and blocks the actions of acetylcholine or cholinergic agonists. It has no effects on muscarinic (mAch) receptors.Mepyramine It is a histamine H1 antagonist and targets the H1- Receptor. Although it was believed to be an antagonist merely to block the actions of endogenous histamine without activating the receptors, it has late been classified as an inverse agonist fall the spontaneous activity of gp-H1r. It also inhibits histamine induced inositol phosphate (InsP) production and intracellular calcium mobilization. It causes a marked decrease in the maximal res ponse to histamine at high concentrations.Atropine It is a competitive antagonist for the muscarinic cholinergic receptor (mAch). It binds to the receptor without activating it, thus blocking the actions of endogenous acetylcholine or exogenic agonists.a) The drug in this experiment were acting on three receptors. H1-Histamine receptors, muscarinic (mAch) receptors and nicotinic (nAch) receptors. severally agonist was acting on a different receptor and that is apparent from our results. When using an antagonist that blocked a specific receptor it only inhibited the action of the drug acting on that particular receptor, and had no effect on the rest of the drugs.b) The receptors were obviously located on the come forth of the muscle, so that the access of the drugs would be possible.The first apparent antagonist which saturnine out to be an agonist was isoprenaline. It acts on the - adrenergic receptors causing muscle relaxation and antagonized all the three agonists who acted on different receptors. This type of antipathy is called a physiological antagonist and describes the interaction of two drugs who cause opposing actions in the body and tend to cancel each other. In this case, the isoprenaline acts on the - adrenergic receptors and causes relaxation of the muscle, whereas the agonist act on the histaminic, nicotinic and muscarinic receptors and cause contraction of the muscle.The second apparent antagonist was mepyramine, which acts on the histamine receptor and blocks the action of histamine. It has recently been classified as an inverse agonist, causing muscle relaxation. This type of agonists steer selectivity to the resting state of the receptor.Atropine acts on the muscarinic receptors and blocks their action. Thus it prevents acetylcholine from binding to the receptor and stimulating it. Nicotine though activates the nicotinic receptor that apparently has nothing to do with atropine. The reversal of nicotine action indicates the posture of i nhibitory postganglionic (terminal) neurones, which respond to stimulation of their ganglion-cells by inducing relaxation of the gut. It is also suggested by other experiments Phillis York, 1968 that an intermediate type of receptor is involved. presumptuous specificity of the antagonist these studies are explained by a non-classical cholinergic receptor with obscure pharmacological properties. Such receptors are the newest members of the nicotinic acetylcholine receptor (nAChR) family, encoded by the 9/10 subunits, that possess a compoundd nicotinic-muscarinic sensitivity.Barium Chloride is a water water-soluble salt. Once in contact with the muscle it induces release of intracellular stores of calcium, and causes the contraction of the muscle. If barium chloride comes in contact with sodium sulphate it loses its potency. That is explained by the chemical substance reaction between the two compounds.Molecular compareBaCl2(aq) + Na2SO4(aq) BaSO4(s) + 2NaCl(aq)ionic equationBa+2 (aq) + 2Cl-(aq) + 2Na+(aq) + SO4-2(aq) BaSO4(s) + 2Na+(aq)+2Cl-(aq)These reactions show that once in contact with sodium sulphate, the barium chloride dissolves into BaSO4 which is an insoluble substance and NaCl. Thus, it can no longer act on the muscle. That type of antagonism is called Chemical Antagonism and it refers to the situation when two substances combine in solution as a result, the effect of the active drug (in this case the barium chloride) is lost.The drugs were tested on guinea pig ileum which is a smooth muscle.