G neurotransmitters

Gated ion channels (e.g. neurotransmitter receptors described under Structure above) ... 

Figure 8 Ubiquitin and endocytosis. Receptors on the plasma membrane undergo monoubiquitination as a result of ligand (e.g., neurotransmitter). Ubiquitinated receptors bind to proteins called epsins, which in turn interact with adaptor proteins (adaptin) bound to clathrin-coated pits. Ubiquitination also functions to sort the internalized membrane protein into early endosomes, which directs them to degradation by lysosome through the multivesicular body. If ubiquitin from the endocytosed receptors is removed by an UBP, the receptor recycles back to the membrane. Proteasome inhibitors block endocytotic degradation of some proteins such as glutamate receptor subunits indicating a possible role for the proteasome.

Receptor A macromolecule or a polymeric structure in or on a cell that specifically recognizes and binds a compound acting as a molecular messenger (e.g. neurotransmitters, hormones, drugs)... 

Other systems (e.g., neurotransmitter, neuropeptides, neurohormonal) may also play important central or modulating roles in the psychotic process ( Table 5-2 and Table 5-3). In addition to dopamine, the following have been implicated ... 

Receptors are glycoproteins imbedded in the lipid bilayer of neuronal membranes and can detect minute amounts of specific ligands (e.g., neurotransmitters, hormones). The ligand-receptor interaction sets in motion a transduction system (e.g., an enzyme, ion channel) that orchestrates various intracellular biochemical events. 

Hayes, R. L., Jenkins, L. W., and Lyeth, B. G., Neurotransmitter-mediated mechanisms of traumatic brain injury. Acetylcholine and excitatory amino acids, J. Neurotrauma, 9 (Suppl. 1), S173, 1992. 

Synaptic vesicles are formed primarily by endocytic budding from the plasma membrane of axon terminals. Endocytosis usually involves clathrin-coated pits and is quite specific, in that several membrane proteins unique to the synaptic vesicles (e.g., neurotransmitter transporters) are specifically incorporated into the endocytosed vesicles. In this way, synaptic-vesicle membrane proteins can be reused and the recycled vesicles refilled with neurotransmitter (see Figure 17-36). 

The process by which eukaryotic cells release packets of molecules v(e.g., neurotransmitters) to the environment by fusing vesicles formed in the cytoplasm with the plasma membrane. 

Of equal interest are proteins of the cytoskeleton that serve structural roles (e.g. tubulin), or those involved in transport processes. For example, many drugs act indirectly by releasing, or preventing the release, of pharmacologically active molecules (e.g. neurotransmitters) concentrated... 

Many of the more interesting membrane proteins (e.g., neurotransmitter receptors) cannot be expressed in sufficiently high concentrations. Membrane proteins in general seem to be a problem for calometry. (j was not able to find a single calometric paper on this.)... 

Most hormones, as well as other chemical signals, e.g. neurotransmitters, have been found to act in one of three ways. They may... 

Fluorescence techniques can be applied to all kinds of material. Because fluorescence microscopy requires more complex and expensive instrumentation than conventional transmitted-light microscopy, fluorescence microscopy is usually reserved for those applications in which its high sensitivity is of importance i.e., to examine substances present in low concentrations. Fluorescence microscopy can also be applied to detect particles below the resolution of a light microscope, and in histochemistry to visualize substances which cannot be seen by conventional microscopy - e.g. neurotransmitter amines. Biological material is commonly stained in some manner with a fluorescent stain. 

Membrane fusion involves the merging of two phospholipid bilayers in an aqueous environment and is involved in many cellular processes, such as cell exocytosis. Synaptic vesicles are nanometersized organelles, which are packaged with chemical messengers (e.g., neurotransmitters, neurohormones, and neuropeptides). Each presynaptic nerve terminal contains hundreds of synaptic vesicles. When an action potential depolarizes the presynaptic plasma membrane, Ca + channels... 

One of the two protocols presented here has been adjusted to process paraformaldehyde-fixed tissues while the second for tissues that require glutaraldehyde fixation since the primary antibodies utilized are developed with immunogens obtained by coupling small molecules (e.g., neurotransmitters) with carrier proteins (for details see AO). The techniques described herein are based on those... 

---