Synaptic plasma membrane

As noted above, synaptic vesicles are not typically generated at the level of the TGN. Instead, they are assembled from endocytosed material retrieved from the synaptic plasma membrane. Synaptic vesicle and plasma membrane lipids and proteins are synthesized in the endoplasmic reticulum and modified in the Golgi apparatus, where they are then packaged in secretory vesicles. These synaptic precursors are delivered to the plasma membrane from the cell body by the constitutive secretory pathway. Synaptic vesicle proteins must be retrieved by clathrin-mediated synaptic vesicle endocytosis, a variant of RME with some neuron-specific components. Once the vesicle sheds its clathrin coat, the uncoated vesicle fuses with a... 

Proteins that reversibly associate with synaptic plasma membrane proteins... 

Nonsteroidal SERMs can also amplify signal-induced Ca2+ surges by inhibiting Ca2+-calmodulin-dependent membrane (Ca2+ + Mg2+)-ATPase. For instance, in synaptic plasma membranes and red cell membrane ghosts, tamoxifen and other triphenylethylene compounds (but not estradiol) have been... 

Jensen, T.P., Filoteo, A., Knopfel, T., Empson, R.M., 2007, Pre-synaptic plasma membrane Ca2+ ATPase isoform 2a regulates excitatory synaptic transmission in rat hippocampal CA3. J Physiol (Lond) 15,... 

In this respect, it is of interest to mention a study by Carvalho etal.[ 122]. These authors studied the partitioning of three calcium antagonists in brain plasma membranes (native synaptic plasma membrane) and compared the determined Kp M values with those obtained from liposomes prepared from lipids extracted from these native membranes. They also compared them with Poet.- Two facts became obvious. First, the ranking of the Kp M values was the same for native membranes and the liposomes made from extracted lipids. The absolute values were, however, much larger for Kp M determined in the native membranes, especially when compared with Poet (Table 4.34). Second, there was a significant increase in Kp m with increase in temperature in native membranes but not in liposomes. This suggests that the presence of membrane proteins positively influenced the uptake of drugs into the native membrane. 

Tab. 4.34 Partition coefficients of Ca2+ antagonists in synaptic plasma membranes (SPM) and liposomes and octanol-water, at 25 °C. (Reprinted from Tab. 1 of ref. 122 with permission from Elsevier Science)...

Fig. 6. Effect of in vivo aluminum exposure on the Ca2+ ATPase activity in synaptic plasma membranes. Values are mean SD of 8 animals/group. P < 0.001, statistically significant from control group. Data are from Julka and Gill (1996) [32]...

Sokolov BP, Tcherepanov AA, Haroutunian V, Davis KL. 2000. Levels of mRNAs encoding synaptic vesicle and synaptic plasma membrane proteins in the temporal cortex of elderly schizophrenic patients. Biol Psychol 48 184-196. 

Prokai, L., Zharikova, A.D. and Stevens, S.M. Jr. (2005) Effect of chronic morphine exposure on the synaptic plasma-membrane subproteomeofrats a quantitative protein profiling study based on isotope-coded affinity tags and liquid chromatography/mass spectrometry. J. Mass Spectrom. 40, 169-175. 

Myers M, Freire E. Calorimetric and fluorescence characterization of interactions between enkephalins and liposomal and synaptic plasma membranes containing gangliosides. Biochemistry 1995 24 4076 082. 

Further studies in our laboratory revealed that chronic treatment with morphine in both rats and mice, on the other hand, produced opposite effects to acute treatment, with significant increases in synaptosomal Ca2+ levels being observed (50, 51, 52). The increases were reported to be localized in the synaptic vesicle fraction (51,52) and synaptic plasma membrane fraction (SPM) (53). Naloxone treatment blocked the increase in Ca2+ levels, while naloxone-precipitated withdrawal resulted in a return to control Ca2+ levels within 15 minutes after injection (50). Both -endorphin and methionine-enkephalin were also noted to cause Ca2+ depletion of synaptic vesicles and SPM after acute treatment ( 3). 

Catecholamine-insensitive specific IBS were described in numerous tissues including the human brain and kidney (Coupry et al., 1987 Langin and Lafontan, 1989 Parini et al., 1989). Bricca et al. (1988) reported that almost 80% of the specific binding of [ H]-clonidine brainstem membranes were insensitive to noradrenaline. While Ij-IBS were clearly shown to be located on the external membrane of the mitochondria (Limon et al., 1992), 1,-IBS are present in synaptic plasma membranes (Heemskerk et al.,... 

Influence of morphine on protein synthesis in synaptic plasma membranes of the rat brain... 

Basavarajappa, B.S., Hungund, B.L. (1999) Down-regulation of caimabinoid receptor agonist-stimulated [35S]GTP gamma S binding in synaptic plasma membrane from chronic ethanol exposed mouse Brain Res. 815, 89-97. 

Tsutsumi, T., Kobayashi, T., Ueda, H., Yamauchi, E., Watanabe, S., and Okuyama, H. (1994) Lysophosphoi-nositide-specific phospholipase C in rat brain synaptic plasma membranes. Neurochemical Research 19 399-406. 

Parcej, D., and Dolly, J. (1989). Oendrotoxin Acceptor from Bovine Synaptic Plasma Membranes, Biochem. J. 257 899-903. 

Barzilai, A., et al. (1984). Isolation, Purification and Reconstitution of the Na Gradient-dependent Ca Transporter (Na -Ca Exchanger) from Brain Synaptic Plasma Membranes, Proc. Natl Acad. Sci. USA 81 6521-6525. 

The externally disposed polypeptides in chick synaptic plasma membranes are glycoproteins, containing non-reducing terminal D-galactosyl residues. A myelin-associated glycoprotein on the surface of rat, bovine, and human myelin membranes is one of the principal receptors for concanavalin A. ... 

Cotman C W and Matthews D A. (1971) Synaptic plasma membranes from rat brain synaptosomes Isolation and partial characterization. Biochem Biophys Acta 249, 380-394... 

Igbavboa U, Avdulov NA, Chochina SV, Wood WG. Transbilayer distribution of cholesterol is modified in brain synaptic plasma membranes of knockout mice deficient in the low-density lipoprotein receptor, apolipoprotein E, or both proteins, f Neurochem. 1997 69 1661-1667. 

Several studies indicate that the bulk of brain ganglioside glycosyltransferases are associated with the synaptosome-rich fractions (Roseman, 1970 Di Cesare and Dain, 1972) and after hypoosmotic shock of the crude mitochondrial fraction they are found in the subfractions enriched in synaptic plasma membranes (Den et al., 1975 ... 

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