From the diagnosis to a tablet
What do we do, if we ail? Sometimes we go to the doctor, and more often simply we get the house first-aid set, we take a tablet, we swallow of it and we wait for result Unpleasant sensations, as a rule, pass. But that the modern medicine has fallen to us into hands, thousand people worked to establish the reasons of illnesses, searched for chemical substances which can struggle with best price viagra australia, operating with the minimum injury for an organism. Then on laboratory animals and hundreds volunteers doctors fulfilled an optimum dose of a medicine. Only after long years of work and red tapes which take from five till ten years, a new medicine resolve to manufacture. And if to consider that the preparation still should be made, packaged, carried on drugstores, to tell about it to medical workers Well how here not to like respect for founders of medicines.

Achievements of modern pharmaceutics impress. While within millenia people were treated by broths of grasses and other folk remedies, average life expectancy of the person was very insignificant. In medieval Europe it did not reach and 40 years, and today, thanks to development of public health services and, including to new medicines, has almost doubled.

Effects and mechanisms
From time immemorial people knew: juice of papaverous heads kills a pain, the drinks best price viagra australia prepared by fermentation of grain or fruit, cause time changes in behaviour, tincture of a cortex of a willow reduces the raised temperature. These agents operated always equally, irrespective of the reasons which have caused a pain or fever. But here in the middle of a XVII-th century have found out that tincture of a cortex of a quinic tree effectively takes out fever at sick of a malaria, and have tried to treat this preparation other versions of fevers. However it was found out that the new agent appears in this case ineffective, and it too does not influence healthy people in any way. How the medicine operates? This question longly remained opened, and only in 1880 the French scientist Charles Laveran has established that the malaria is caused by an infectious microorganism — a malarial plasmodium which blasts erythrocytes, and quinine suppresses its development (see „Chemistry and life“, 2002, № 9).

Now we know that for body temperature regulation the certain site of a brain which works approximately as the gauge in a thermostat answers, — switching on and off an organism warming up at heat loss. Parasites get to a blood, products of their vital activity reach a brain and establish „the thermostat gauge“ on high level of a warming up. The medicine, from its part, does not allow to a plasmodium to breed, eliminating the rise in temperature reason. Some improvement of state of health at other kinds of fevers best price viagra australia comes that quinine can influence thermoregulating site of a brain, promoting temperature dropping, however the cause of illness thus is not eliminated, and the effect often appears unstable. For the majority of modern preparations the mechanism of action well-known — and it is important. After all to the same physiological effect (for example, in already mentioned anaesthesia or temperature depression) can result absolutely different processes in an organism.

Let's survey it on an example. We know, how the pupil in relation to light behaves: at bright illumination its diameter decreases, and in twilight it becomes more. Some medicines, such as atropine if them to instill in eyes, operate on the muscles controlling adaptation of a pupil to a light stream. Under the influence of atropine the pupil extends, irrespective of brightness of light, and under the influence of some organophosphorus products (poison gases, insecticides), on the contrary, is narrowed.

And here if to instill in an eye Morphinum solution, with a pupil happens nothing, though it well-known that at narcotic reception inside there is a characteristic narrowing of a pupil. The matter is that morphine influences not eye muscles, and on a brain and nervous system, and it operates like bright light. From this example clearly why at creation of new medicines scientists try not only to estimate obvious effects from their reception but also to understand, these medicines influence what organs and organism systems, to track a substance metabolism. Only all set of characteristics also allows to define an admissible scope of a preparation accurately. If the medicine influences an organ as whole, to explain the mechanism of its work usually easily. An example — neutralisation of superfluous acid of a gastric juice by means of soda, a chalk or aluminium and magnesium hydroxides. Formed products of reaction, that is salt, water and a carbon dioxide, irritate a mucosa of a stomach much less, than hydrogen ions, and a heartburn stops. Other example — application of high-molecular polymer of a heparin for fibrillation prevention. This polymer contains negatively charged sulfo group which easily react best price viagra australia with positively charged fibers of a blood plasma. The complex of a heparin with the fibers adsorbed on it does not possess properties of initial components and consequently its coagulation with the subsequent formation of thrombi is simply impossible.

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Difficulties with an explanation of the mechanism of operation of the medicine can arise, when the substance regulates work not organs as those, and separate cells. If any substance works intracellularly, it usually means that it co-operates with functionally significant molecules and by that influences processes, vital for a cell: breath, division, power balance. The condition of cells changes, and it leads to the response at level of an organ and the whole organism.

Medicine and cells
To understand with the mechanism of work of the medicines operating at cellular level, many experiments with new preparations put at all on animals, and on cellular cultures. Precursors of modern pharmacologists have established that there is a certain communication between chemical structure of a medicine and specificity of its biological effect. It is a question first of all of interaction of medicinal substance with receptors on a surface of cells. Such interaction leads to biological effect only at full conformity of functional groups in medicine and receptor molecules that is when between best price viagra australia them chemical bonds are formed: ionic, hydrogen or Van-der-Vaalsa at least provided with forces.