Receptor proteolipids

Recently Saraceno De Robertis (1976) found that the cholinergic receptor proteolipid protein isolated by affinity chromatography from bovine caudate nucleus probably contained 90 % muscarinic sites and only 10% nicotinic. 

Gudz, T. I., Schneider, T. E., Haas, T. A. et al. Myelin proteolipid protein forms a complex with integrins and may participate in integrin receptor signaling in oligodendrocytes. /. Neurosci. 22,7398-7407, 2002. 

Another, but less well defined, class of molecules, some of whose members mediate adhesion interaction, is the four-transmembrane domain family, which shares similar hydropathy plots and may have similar dispositions with respect to the phospholipid bilayer, for example the myelin proteolipid proteins, the connexins of gap junctions, the ryanodine receptor and others. 

Alves, I. D. Cowell, S. M. Salamon, Z. Devanathan, S. Tollin, G. Hruby, V. J., Different structural states of the proteolipid membrane are produced by ligand binding to the human 8 opioid receptor as shown by plasmon waveguide resonance spectroscopy, Mol. Pharmacol. 2004, 65, 1248 1257... 

The cell membrane has receptor sites referred to as reactive cellular sites. Receptor sites on cell membranes are proteins, glycoproteins, proteolipids, or enzymes. 

The pharmaceutical response is realized when a dmg binds to a receptor on the cell membrane. These are referred to as reactive cellular sites. The activity of the dmg is determined by the dmg s ability to bind to a specific receptor. The better the fit, the more biologically active the dmg. Receptors are proteins, glycoproteins, proteolipids, or enzymes. Depending on the dmg, binding either initiates a physiological response by the cell or blocks a cell s physiological response. 

It has been known since the work of Rona et al. (1959) that sympathomimetic amines at dose levels, which would be lethal for humans produce extensive necrosis in the rat myocardium. The lesions and those produced in the same species by hypoxia have morphological features in common (Niles et al. 1968). A proteolipid binding H-isoprenaline was localized in the plasma membrane of the feline heart ventricular myocytes (Ochoa et al. 1972). Exposing myocytes to catecholamines lead to down-regulation of the number of receptors within minutes (Linden et al. 1984). 

It is interesting that by affinity chromatography Meunier et al., (1974) reported the extraction of 2.9 mg/Kg of cholinergic receptor from the Electropborus. In the original paper of La Torre et al., (1970) is already stressed the higher amount of proteolipid present in the Torpedo electroplax as compared with the Electropborus. 

To investigate further the problem of the relationship between the cholinergic proteolipid and the proteodetergent, receptor-enr ched membranes from Torpedo electroplax were submitted to SDS polyacrylamide gel electrophoresis using the discontinuous buffer system of Laemmli (1970) as modified for slab gels by Studier (1973). 

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