Summary
Rat hippocampal slices were exposed briefly (12–15 min) to AlF4- (10 mmol/l NaF, 10 μmol/l AlCl3). The effect on synaptic transmission in area CAl was measured using extracellular electrodes placed in the stratum pyramidale and stratum radiatum. During fluoride exposure, both spike and EPSP amplitude fell to very low levels. Upon washout, spike amplitude recovered beyond control values, and in half of the preparations a prolonged enhancement of spike amplitude (> 2 h) occurred. Similar modulation of EPSP slope indicated that these charges were primarily synpatic. If Al3+ was omitted from the F--containing saline, enhancement of spike amplitude, when observed, was brief (20–30 min) and no enhancement of EPSP slope was seen. Omission of Ca2+ from the AlF4--containing saline also abolished any long-lasting enhancement of synaptic transmission, though population spike amplitude in most slices showed a brief (20–30 min) stimulatory response. In preparations in which LTP had previously been saturated, synaptic transmission was not enhanced by exposure to AlF4-. It is concluded that NaF/ACl3 exposure induces an LTP-like process by G-protein activation, which involves recruitment of processes involved in LTP, possibly including an enhancement of Ca2+-influx.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Adams DJ, Oxford GS (1983) Interaction of internal anions with potassium channels of the squid giant axon. J Gen Physiol 82:429–448
Anwyl R (1989) Protein kinase C and long-term potentiation in the hippocampus. Trends Pharmacol Sci 10:236–239
Berridge MJ, Irvine RF (1989) Inositol phosphates and cell signalling. Nature 341:197–205
Bigay J, Deltere P, Pfister C, Charbre M (1985) Fluoroaluminates activate transducin-GDP by mimicking the a-phosphate of GTP in its binding site. FEBS Lett 191:181–185
Bigay J, Deltere P, Pfister C, Charbre M (1987) Fluoride complexes of aluminium and beryllium act on G-proteins as reversibly bound analogues of the γ-phosphate of GTP. EMBO J 6:2907–2913
Blackmore PF, Bocckino SB, Waynick LE, Exton JE (1985) Role of guanine nucleotide binding protein in the hydrolysis of hepatocyte phosphotidylinositol 4,5 bisphosphate by calciummobilising hormones and the control of cell calcium: studies using aluminium fluoride. J Biol Chem 260:14477–14483
Bliss TVP (1990) Maintainence is presynaptic. Nature 346:698–699
Collingridge GL, Bliss TVP (1987) NMDA receptors: their role in long-term potentiation. Trends Neurosci 10:288–293
Collingridge GL, Herron CE, Lester RAJ (1985) Frequency dependent N-methyl-D-aspartate receptor-mediated synaptic transmission in rat hippocampus. J Physiol 399:301–312
Furuya S, Ohmori H, Shigemoto T, Sugiyama H (1989) Intracellular calcium mobilisation triggered by a glutamate receptor in rat cultured hippocampal cells. J Physiol 414:539–548
Goh JW, Pennefather PS (1989) A pertussis toxin-sensitive G protein in hippocampal long-term potentiation. Science 244:980–983
Ito I, Okada D, Sugiyama H (1988) Pertussis toxin suppresses long-term potentiation of hippocampal mossy fibre synapses. Neurosci Lett 90:181–185
Kay AR, Miles R, Wong RKS (1986) Intracellular fluoride alters the kinetic properties of calcium currents facilitating the investigation of synaptic events in hippocampal neurons. J Neurosci 6:2915–2920
Kennedy MB (1985) Regulation of synaptic transmission in the central nervous system: long-term potentiation. Cell 59:777–787
Litosch I (1987) Guanine nucleotides and NaF stimulation of phospholipase C activity in rat cerebral cortical membranes: studies on substrate specificity. Biochem J 244:35–40
Lynch G, Baudry M (1984) The biochemistry of memory: a new and specific hypothesis. Science 224:1057–1063
Lynch G, Larson J, Kelso S, Barrionuevo G, Schottler F (1983) Intracellular injections of EGTA block induction of hippocampal long-term potentiation. Nature 305:719–721
Lynch MA, Clements MP, Errington ML, Bliss TVP (1988) Increased hydrolysis of phosphotidylinositol-4, 5-bisphosphate in long-term potentiation. Neurosci Lett 84:291–296
Malenka RC, Kauer JA, Perkel DJ, Mauk MD, Kelly PT, Nicoll RA, Waxman MN (1989) An essential role for postsynaptic calmodulin in long-term potentiation. Nature 340:554–557
Malinow R, Schulman H, Tsien RW (1989) Inhibition of postsynaptic PKC and CaMK II blocks induction but not expression of LTP. Science 245:862–866
Murphy SN, Miller RJ (1988) A glutamate receptor regulates Ca2+ mobilisation in hippocampal neurons. Proc Nat Acad Sci USA 85:8737–8741
Ribeiro JA, Sebastiano AM (1985) Inhibitory effects of forskolin and papaverine on nerve conduction partially blocked by tetrodotoxin in the frog sciatic nerve. Br J Pharmacol 85:309–313
Scharfman HE, Sarvey JM (1985) Postsynaptic firing during repetitive stimulation is required for long-term potentiation in hippocampus. Brain Res 331:267–274
Sternweiss PC, Gilman AG (1982) Aluminium, a requirement for activation of the regulatory component of adenylate cyclase by fluoride. Proc Nat Acad Sci USA 79:4888–4891
Williams JH, Bliss TVP (1989) An in vitro study of the effect of lipoxygenase and cyclo-oxygenase inhibitors of arachidonic acid on the induction and maintenance of long-term potentiation in hippocampus. Neurosci Lett 107:1–3
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Publicover, S.J. Brief exposure to the G-protein activator NaF/AlCl3 induces prolonged enhancement of synaptic transmission in area CAl of rat hippocampal slices. Exp Brain Res 84, 680–684 (1991). https://doi.org/10.1007/BF00230983
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00230983