Synaptosomes calcium uptake

Ramadan, A.A., N.M. Bakry, A.S.M. Marei, A.T. Eldefrawi, and M.E. Eldefrawi. 1988. Action of pyrethroids on K+-stimulated calcium uptake by, and (3H)nimodipine binding to, rat brain synaptosomes. Pestic. Biochem. Physiol. 32 114-122. 

Doherty JD, Nishimura K, Kurihara N, Fujita T (1987) Promotion of norepinephrine release and inhibition of calcium uptake by pyrethroids in rat brain synaptosomes. Pestic Biochem Physiol 29 187-196... 

Mercuric chloride is thought to gain access to the intracellular compartment through Na + and Ca2 + channels in the membrane [ 100]. Sulphydryl reagents, including Hg2 +, could inhibit K +-stimulated uptake of Ca2+ into rat brain synaptosomes in vitro [101]. In muscle sarcoplasmic reticulum, Hg2+ causes inhibition of ATP-dependent Ca2 + uptake and loss of accumulated calcium [ 102,103]. However, HgCl2 has been found to inhibit ATP-dependent calcium uptake more strongly than it inhibits potassium-stimulated uptake [ 104],... 

At the cellular level, chlordecone causes spontaneous neurotransmitter release (End et al. 1981) and increases in free intracellular calcium in synaptosomes (Bondy and Halsall 1988 Bondy and McKee 1990 Bondy et al. 1989 Komulainen and Bondy 1987). This appears to be due at least in part to increased permeability of the plasma membrane (Bondy and Halsall 1988 Bondy and McKee 1990 Bondy et al. 1989 Komulainen and Bondy 1987), activation of voltage-dependent calcium channels (Komulainen and Bondy 1987), and inhibition of brain mitochondrial calcium uptake (End et al. 1979, 1981). 

The pharmacokinetics of morphine have been studied,201-203 as has its receptor binding,204-206 and its effects on hypothermia,207 on calcium uptake by synaptosomes208 and lysed synaptosomes,209 on metabolism of catecholamine in brain,210 on levels of corticosteroids and growth hormone in plasma,211 on leuteinising hormone,212 follicle-stimulating hormone,212 and prolactin,212-215 on neuroendocrine function,216 on brain function and biochemistry,217-226 on behaviour,227-240 on the gastrointestinal tract241 and on the cardiovascular... 

BHC produces a variety of neurological effects in insects and mammals. However, at both levels of the nervous system (peripheral and central), the mechanism of toxic action of BHC is poorly understood. Central nervous system stimulation appears to be due to blockade of the effects of y-aminobutyric acid. In vitro BHC isomers are reported to increase the calcium uptake of isolated rat brain synaptosomes. In addition, y-isomer of BHC has been shown to inhibit... 

Phenytoin also affects calcium uptake in synaptosomes. Similar to Mn, it inhibits the action of both veratridine and K, but like tetrodotoxin it is much more effective against veratridine (Figure 2). Stimulated Ca uptake produced at all concentrations of K between 15 and 64 mM is inhibited 20% by 0.1 mM phenytoin, and this is unaffected by tetrodotoxin. Examination of the dose-related effect of phenytoin on stimulated Ca uptake produced by 23 and 64 mM K reveals identical proportional inhibition of both. Thus, inhibition of K-induced Ca uptake by phenytoin is independent of K concentration. In contrast, there appears to be a competitive interaction between veratridine and phenytoin. Phenytoin has a much greater inhibitory effect, proportionally, on Ca uptake stimulated by low concentrations of veratridine than that produced by higher concentrations. For example, 35 yM phenytoin caused 50% inhibition of Ca uptake produced by 5 yM veratridine, but 225 yM phenytoin is required for 50% inhibition of the Ca uptake produced by 100 yM veratridine. 

Inhibitory Effects of Hydantoins on K- and Veratridine-Stimulated Calcium Uptake in Synaptosomes... 

PCP also increases calcium-independent [3H]DA release from dissociated rat mesencephalon cell cultures122 and striatal synaptosomes.123 PCP has been found to be a potent inhibitor of [3H]DA uptake in rat striatum,124 127 to competitively inhibit binding of [3H]BTCP, a PCP derivative and... 

Hemicholinium blocks the transport of choline into synaptosomes, whereas botulinum toxin blocks the calcium-mediated release of acetylcholine. The released acetylcholine is hydrolyzed rapidly by acetylcholinesterase to choline and acetate. Ginseng enhances the uptake of choline and facilitates the release of acetylcholine. 

A similar prejunctional CEB effect was found for diltlazem in guinea pig mesenteric and dog basilar arterial preparations. Clnnarizlne and flu-narizine were shown more potent than verapamil, diltlazem or nifedipine in reducing the potassium-induced uptake of calcium in a synaptosomal prepara-... 

Apnson M H and McBnde W. ] (1973) Evidence for the net accumulation of glycine into a synaptosomal fraction isolated from the telencephalon and spinal cord of the rat Life Set 7, 583-590. Baker P F and Glitsch H G (1975) Voltage-dependent changes in the permeability of nerve membranes to calcium and other divalent cations Phil, Trans Roy Soc (B) 270, 389-409 Beart P. M., Kelly]. S, and Schon F. (1974) 7-Aminobutyric acid uptake in the rat peripheral nervous system, pineal, and posterior pituitary Biochem Soc Trans 2, 26 268 Benjamin A M and Quastel ] H. (1972) Locations of amino acids in brain slices from the rat. Tetrodotoxm-sensitive release of amino acids Biochem J 128, 631-646... 

Roberts P J (1976) Gamma-aminobutyric acid homoexchange in sensory ganglia Brain Res 113, 206-209 Roskoski R (1978) Net uptake of L-glutamate and GABA by high-affinity synaptosomal transport systems / Neurochem 31, 493-498 Rubin R P (1970) The role of calcium in the release of neurotransmitter substances and hormones Pharmacol Rev 22, 389-498. 

Shih, T.-M. and Hanin, I. (1978b). Chronic lead exposure in immature animals neurochemical correlates. Life ScL, 23, 877 Shirabe, T. and Hirano, A. (1977). X-ray microanalytical studies of lead-implanted rat brains. Acta Neuropathol, (Berlin), 40, 189 Silbergeld, E. K. (1977). Interactions of lead and calcium on the synaptosome uptake of dopamine and choline. Life Sci, 20, 309 Silbergeld, E. K. and Adler, H. S. (1977). Subcellular mechanisms of lead neurotoxicity. Brain Res, 148, 451... 

Although the precise role of taurine In retina Is not completely known there Is evidence that It can play an Inhibitory transmitter pole (16, 17) since It Is able to affect potassium and calcium fluxes at the Ionic membrane level (18-20), At the light of these findings It Is easily Interpreted the functional Inhibitory role of taurine In experiments In which from perfused chick and rat retina preloaded with 35S-taurlne light flashes enhance endogenous and labeled taurine release (21,22), Taurine Is the most potent amino acid able to reversibly abolish electroretinogram b wave (23-25) as well as to depress several neuronal populations from cerebral cortex, subcortical areas and spinal cord (26-29), In addition a specific uptake system has been described to occur In rat retina (30, 31) as well as In retinal pigment epithelium (32) and In slices and synaptosome preparations from various areas of the brain (33, 34),... 

---