The acoustic analyzer perceives the sound signals representing fluctuations of air with different frequency and force, transforms mechanical energy of these fluctuations to nervous excitation which is subjectively perceived as sound sensation. Purchase flagyl metronidazole Pervichnochuvstvujushchie receptors are the bipolar touch nervous cages supplied with eyelashes which like aerials conduct "search" of an adequate irritant. Contact to an irritant leads to occurrence рецешпорного potential which электротонически extends to аксону touch нейрона where it is formed ПД, extending on a nervous fibre. Because the basic representative of preparations of this group - пирацетам is synthetic analogue brake медиатора ГАМК, probably, that пирацетам is capable to strengthen brake processes in a brain. Besides, this preparation strengthens synthesis дофамина and raises level норадреналина, some ноотропы increase the maintenance ацетилхолина and серотонина in a nervous fabric. Feature ноотропов is their stimulating influence on metabolic and biopower processes in nervous cages.