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Pyridostigmine brain penetration under stress enhances neuronal excitability and induces early immediate transcriptional response


Pyridostigmine, a carbamate acetylcholinesterase (AChE) inhibitor, is routinely employed in the treatment of the autoimmune disease myasthenia gravis1. Pyridostigmine is also recommended by most Western armies for use as pretreatment under threat of chemical warfare, because of its protective effect against organophosphate poisoning2,3. Because of this drug's quaternary ammonium group, which prevents its penetration through the blood–brain barrier, the symptoms associated with its routine use primarily reflect perturbations in peripheral nervous system functions1,4. Unexpectedly, under a similar regimen, pyridostigmine administration during the Persian Gulf War resulted in a greater than threefold increase in the frequency of reported central nervous system symptoms5. This increase was not due to enhanced absorption (or decreased elimination) of the drug, because the inhibition efficacy of serum butyrylcholinesterase was not modified5. Because previous animal studies have shown stress–induced disruption of the blood–brain barrier6, an alternative possibility was that the stress situation associated with war allowed pyridostigmine penetration into the brain. Here we report that after mice were subjected to a forced swim protocol (shown previously to simulate stress7), an increase in blood–brain barrier permeability reduced the pyridostigmine dose required to inhibit mouse brain AChE activity by 50% to less than 1/100th of the usual dose. Under these conditions, peripherally administered pyridostigmine increased the brain levels of c–fos oncogene and AChE mRNAs. Moreover, in vitro exposure to pyridostigmine increased both electrical excitability and c–fos mRNA levels in brain slices, demonstrating that the observed changes could be directly induced by pyridostigmine. These findings suggest that peripherally acting drugs administered under stress may reach the brain and affect centrally controlled functions.

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  1. Taylor, P. Cholinergic agonists. and Anticholinesterase agents. in The Pharmacological Basis of Therapeutics, 8th edn (eds. Gilman, A.G., Rall, T.W., Nies, A.S. & Taylor, P.) 122–130, 131–147 (Pergamon, New York, 1990).

    Google Scholar 

  2. Deyi, X., Linxiu, W. & Shuqiu, P. The inhibition and protection of cholinesterase by physostigmine and pyridostigmine against soman poisoning in vivo . Fundam. Appl. Toxicol. 1, 217–221 (1981).

    Article  Google Scholar 

  3. Diruhumber, P., French, M.C., Green, D.M., Leadbeater, L. & Stratton, J.A. The protection of primates against soman poisoning by pretreatment with pyridostigmine. J. Pharmacol. 31, 295–299 (1979).

    Article  Google Scholar 

  4. Borland, R.G., Breman, D.H. & Nicholson, A.N. Studies on the possible central and peripheral effects in man of a cholinesterase inhibitor (pyridostigmine). Hum. Toxicol. 4, 293–300 (1985).

    Article  CAS  Google Scholar 

  5. Sharabi, Y. et al. Survey of symptoms following intake of pyridostigmine during the Persian Gulf War. Isr. J. Med. Sci. 27 656–658 (1991).

    CAS  Google Scholar 

  6. Sharma, H.S., Cervos-Navarro, J. & Dey, P.K. Increased blood–brain barrier permeability following acute short-term swimming exercise in conscious normotensive young rats. Neurosci. Res. 10, 211–221 (1991).

    Article  CAS  Google Scholar 

  7. Melia, K.M., Ryabinin, A.E., Schroeder, R., Bloom, F.E. & Wilson, M.C. Induction and habituation of immediate early gene expression in rat brain by acute and repeated restraint stress. J. Neurosci. 14, 5929–5938 (1994).

    Article  CAS  Google Scholar 

  8. Ben Aziz-Aloya, R. et al. Expression of a human acetylcholinesterase promoter-reporter construct in developing neuromuscular junctions of Xenopus embryos. Proc. Natl. Acad. Sci. USA 90, 2471–2475 (1993).

    Article  CAS  Google Scholar 

  9. Blick, D.W. et al. Acute behavioral toxicity of pyridostigmine or soman in primates. Toxicol. Appl. Pharmacol. 126, 311–318 (1994).

    Article  CAS  Google Scholar 

  10. Friedman, A. & Gutnick, M.J. Intracellular calcium and control of burst generation in neurons of guinea-pig neocortex in-vitro . Eur. J. Neurosci. 1, 374–381 (1989).

    Article  Google Scholar 

  11. Glickson, M. et al. The influence of pyridostigmine on human neuromuscular functions — studies in healthy human subjects. Fundam. Appl. Toxicol. 16, 288–298 (1991).

    Article  Google Scholar 

  12. Ekstrom, T.J., Klump, W.M., Getman, D., Karin, M. & Taylor, P. Promoter elements and transcriptional regulation of the acetylcholinesterase gene. DNA Cell Biol. 12, 63–72 (1993).

    Article  CAS  Google Scholar 

  13. Ehrhart-Bornstein, M. et al. Adrenaline stimulates cholesterol side-chain cleavage cytochrome P450 mRNA accumulation in bovine adrenocortical cells. J. Endocrinol. 131, 5–8 (1991).

    Article  Google Scholar 

  14. Brust, P. Blood–brain-barrier transport under different physiological and pathophysiological circumstances including ischemia. Exp. Pathol. 42, 213–219 (1991).

    Article  CAS  Google Scholar 

  15. Harik, S.I. & Kalaria, R.N. Blood–brain-barrier abnormalities in Alzheimer's disease. Ann. N. Y. Acad. Sci. 640, 47–52 (1991).

    Article  CAS  Google Scholar 

  16. Agnoli, A., Martucci, N., Manna, V., Conti, L. & Fioravanti, M. Effect of cholinergic and anticholinergic drugs on short term memory in Alzheimer's dementia: A neuropsychological and computerized electroencephalographic study. Clin. Neuropharmacol. 6, 311–323 (1983).

    Article  CAS  Google Scholar 

  17. Iwasaki, Y., Wakata, N. & Sinoshita, M. Parkinsonism induced by pyridostigmine. Acta Neurol. Scand. 78, 236 (1988).

    Article  CAS  Google Scholar 

  18. Loewenstein-Lichtenstein, Y. et al. Genetic predisposition to adverse consequences of anti-cholinesterases in ‘atypical’ BCHE carriers. Nature Med. 1, 1082–1085 (1995).

    Article  CAS  Google Scholar 

  19. Whittaker, M. Cholinesterases. Monogr. Hum. Genet. 65–85 (1986).

  20. Schwarz, M., Click, D., Loewenstein, Y. & Soreq, H. Engineering of human Cholinesterases explains and predicts diverse consequences of administration of various drugs and poisons. Pharmacol. Ther. 67, 283–321 (1995).

    Article  CAS  Google Scholar 

  21. Brown, D.A. Slow cholinergic excitation - a mechanism for increasing neuronal excitability. Trends Neurosci. 6, 302–306 (1983).

    Article  Google Scholar 

  22. McEwen, B.S. & Sapolsky, R.M. Stress and cognitive function. Curr. Opin. Neurobiol. 5, 205–216 (1995).

    Article  CAS  Google Scholar 

  23. Gavaghan, H. NIH panel rejects Persian Gulf syndrome. Nature 369, 8 (1994).

    Article  CAS  Google Scholar 

  24. Ben-Nathan, D., Lustig, S. & Danenberg, H.D. Stress-induced neuroinvasiveness of a neurovirulent noninvasive Sindbis virus in cold or isolation subjected mice. Life Sci. 48, 1493–1500 (1991).

    Article  CAS  Google Scholar 

  25. Neville, L.F., Gnatt, A., Padan, R., Seidman, S. & Soreq, H. Anionic site interactions in human butyrylcholinesterase disrupted by two single point mutations. J. Biol. Chem. 265, 20735–20738 (1990).

    CAS  PubMed  Google Scholar 

  26. Seidman, S. et al. Synaptic and epidermal accumulations of human acetylcholinesterase are encoded by alternative 3′-terminal exons. Mol. Cell. Biol. 15, 2993–3002 (1995).

    Article  CAS  Google Scholar 

  27. Uyama, O. et al. Quantitative evaluation of vascular permeability in the gerbil brain after transient ischemia using Evans blue fluorescence. J. Cerebral Blood Flow Metab. 8, 282–284 (1988).

    Article  CAS  Google Scholar 

  28. Rachinsky, T.L. et al. Molecular cloning of mouse acetylcholinesterase: Tissue distribution of alternatively spliced mRNA species. Neuron 5, 317–327 (1990).

    Article  CAS  Google Scholar 

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Friedman, A., Kaufer, D., Shemer, J. et al. Pyridostigmine brain penetration under stress enhances neuronal excitability and induces early immediate transcriptional response. Nat Med 2, 1382–1385 (1996).

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