SérotonineLa sérotonine, encore appelée 5-hydroxytryptamine (5-HT), est une monoamine de la famille des indolamines. C'est un neurotransmetteur dans le système nerveux central et dans les plexus intramuraux du tube digestif, ainsi qu'un autacoïde (hormone locale) libéré par les cellules entérochromaffines et les thrombocytes. La production de sérotonine a aussi été observée dans le placenta des souris et de l'humain. Elle est majoritairement présente dans l'organisme en qualité d'autacoïde.
Hyperpolarization (biology)Hyperpolarization is a change in a cell's membrane potential that makes it more negative. It is the opposite of a depolarization. It inhibits action potentials by increasing the stimulus required to move the membrane potential to the action potential threshold. Hyperpolarization is often caused by efflux of K+ (a cation) through K+ channels, or influx of Cl– (an anion) through Cl– channels. On the other hand, influx of cations, e.g. Na+ through Na+ channels or Ca2+ through Ca2+ channels, inhibits hyperpolarization.
Escargot de merSea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the absence of a visible shell. Determining whether some gastropods should be called sea snails is not always easy. Some species that live in brackish water (such as certain neritids) can be listed as either freshwater snails or marine snails, and some species that live at or just above the high tide level (for example, species in the genus Truncatella) are sometimes considered to be sea snails and sometimes listed as land snails.
EscargotLe terme escargot est un nom vernaculaire qui en français désigne des gastéropodes à coquille, généralement terrestres et appelés aussi des limaçons, ou colimaçons par opposition aux limaces. Ce sont tous des mollusques, quelle que soit leur taille (le plus petit escargot mesure à peine un millimètre de diamètre, tandis que le plus grand escargot mesure 20 cm) ou leur forme. 40 % des mollusques étant des escargots terrestres, certains escargots toutefois sont des espèces aquatiques, plutôt d'eau douce : Basommatophora tels les limnées ou les planorbes, souvent appelés « escargots nettoyeurs » par les amateurs d'aquariophilie.
Land snailA land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. Land snail is the common name for terrestrial gastropod mollusks that have shells (those without shells are known as slugs). However, it is not always easy to say which species are terrestrial, because some are more or less amphibious between land and fresh water, and others are relatively amphibious between land and salt water.
Freshwater snailFreshwater snails are gastropod mollusks that live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs to major rivers. The great majority of freshwater gastropods have a shell, with very few exceptions. Some groups of snails that live in freshwater respire using gills, whereas other groups need to reach the surface to breathe air. In addition, some are amphibious and have both gills and a lung (e.
Hill equation (biochemistry)In biochemistry and pharmacology, the Hill equation refers to two closely related equations that reflect the binding of ligands to macromolecules, as a function of the ligand concentration. A ligand is "a substance that forms a complex with a biomolecule to serve a biological purpose" (ligand definition), and a macromolecule is a very large molecule, such as a protein, with a complex structure of components (macromolecule definition). Protein-ligand binding typically changes the structure of the target protein, thereby changing its function in a cell.
MyofibrilleA myofibril (also known as a muscle fibril or sarcostyle) is a basic rod-like organelle of a muscle cell. Skeletal muscles are composed of long, tubular cells known as muscle fibers, and these cells contain many chains of myofibrils. Each myofibril has a diameter of 1–2 micrometres. They are created during embryonic development in a process known as myogenesis. Myofibrils are composed of long proteins including actin, myosin, and titin, and other proteins that hold them together.
BupropionLe bupropion (parfois appelé bupropione), commercialisé sous les marques Zyban, Wellbutrin, Voxra, Budeprion et Aplenzin par le laboratoire GlaxoSmithKline, est un psychotrope psychorégulateur prescrit en tant qu'aide au sevrage tabagique et antidépresseur. Accompagné d'un soutien et d'un suivi psychologique, il a obtenu en France une autorisation de mise sur le marché (AMM) en tant qu'aide au sevrage tabagique en août 2001.
GastropodaLes gastéropodes (Gastropoda, du grec ancien , « ventre » et , « pied » : ventre-pied) sont une classe de mollusques caractérisés par la torsion de leur masse viscérale. Ils présentent une très grande diversité de formes mais peuvent se reconnaitre généralement par leur coquille dorsale torsadée et univalve caractéristique lorsqu’elle est présente. Ils possèdent un pied et une tête distincts. Leur pied est aplati en une large sole ventrale, servant à la natation ou la reptation, tandis que leur tête comporte des yeux et une radula.
