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The development of confocal microscopy
Reply from Taylor SIR: Dr Dragunow raises several points that relate in vivo findings to the in vitro experiments discussed in my brief review I. He questions whether loss of GABAergic inhibition could cause seizures produced by kindling. I previously mentioned that there was stronger evidence of GABAergic involvement in brief paroxysmal depolarizations (interictal spikes) than in seizures such as those seen in kindled animals or human epilepsy. It is also clear that loss of GABAergic inhibition is not the only factor involved in seizure onset (for
The development of confocal microscopy SIR: The techniques article on confocal microscopy 1 provided an excellent overview of an important anatomical technique in which very significant advances have been made recently. However, one historical point was perhaps misleading: the confocal scanning laser microscope (CSLM) has a considerably longer history than the three years or so indicated.
example, changes in extracellular ion concentration and perhaps electrical field effects are also involved). However, a GABA hypothesis for seizures cannot yet be dismissed. Although benzodiazepines do not raise afterdischarge thresholds in kindled rats, GABA uptake inhibitors do so to a great extent 2, and GABA transaminase enzyme inhibitors elevate afterdischarge thresholds 3 and prevent partial seizures in humans 4. Other studies suggest that GABAergic inhibition decreases during the kindling process5'6. (However, this is controversial, see also Ref. 7.) The continuing controversy over the involvement of GABA in epilepsy sug-
The first mechanically scanned laser confocal microscope was built at Yale in the early 1970s 2, for which a US Patent was awarded 3, as a direct continuation of the work on the tandem scanning microscope 4'5 cited by Fine et aP. The first CSLM photomicrographs of histologically recognizable cells were published in 19736. M. David Egger Professorand Acting Chairman,Departmentof Anatomy, UMDNJRobert WoodJohnsonMedical School, Piscataway,NJ 08854 5635, USA.
gests that a unitary theory of seizure onset is unlikely. Charles Taylor Parke-Davis PharmaceuticalResearchDivision, 2800 Plymouth Road, Ann Arbor, MI 48105 2430, USA.
References 1 Taylor, C. P. (1988) Trends Neurosci. 11,375-378 2 Schwark, W. S. and Loescher, W. (1985) N. S. Arch. Pharmacol. 329, 367-371 3 Shin, C., Rigsbee, L. C. and McNamara, J. O. (1986) Brain Res. 398,370-374 4 Hammond, E. J. and Wilder, B. J. (1985) Gen. PharmacoL 16, 441-447 5 Morimoto, K. and Goddard, G. V. (1986) Exp. Neurol. 94, 571-584 6 Michelson, H. B. etal. (1988) Epilepsia 29,658-659 7 Tuff, L. P., Racine, R. J. and Adamec, R. (1983) Brain Res. 277, 79-90
References 1 Fine, A., Amos, W. B., Durbin, R. M. and McNaughton, P. A. (1988) Trends Neurosci. 11, 346-351 2 Davidovits, P. and Egger, M. D. (1971) Applied Optics, 10, 1615-1619 3 Davidovits, P. and Egger, M. D. (1972) US Patent No. 3643015 4 Egger, M. D. and Petran, M. (1967) Science 157, 305-307 5 Petran, M., Hadravsky, M., Egger, M. D. and Galambos, R. (1968) J, Opt. Soc. Amer. 58, 661-664 6 Davidovits, P. and Egger, M. D. (1973) Nature 244, 366-367
Order your own personal copy of TINS special issues Additional copies of the TINS October special issue 'Calcium and neuronal excitability' can be obtained at a cost of $10.00/£6.00 each*, with discounts available on orders of 10 or more copies. Payment must accompany your order, and may be made by cheque (made outto Elsevier) or by credit cards. We accept Amex, Visa and Access/Mastercard/Eu rocard. * Price vafid until December 1989.
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Send copies of this order form to: Trends in Neurosciences, Elsevier Publications Cambridge, 68 Hills Road, Cambridge, CB2 1LA, UK.
TINS, VoL 12, No. 1, 1989
11
The development of confocal microscopy SIR: The techniques article on confocal microscopy 1 provided an excellent overview of an important anatomical technique in which very significant advances have been made recently. However, one historical point was perhaps misleading: the confocal scanning laser microscope (CSLM) has a considerably longer history than the three years or so indicated.
example, changes in extracellular ion concentration and perhaps electrical field effects are also involved). However, a GABA hypothesis for seizures cannot yet be dismissed. Although benzodiazepines do not raise afterdischarge thresholds in kindled rats, GABA uptake inhibitors do so to a great extent 2, and GABA transaminase enzyme inhibitors elevate afterdischarge thresholds 3 and prevent partial seizures in humans 4. Other studies suggest that GABAergic inhibition decreases during the kindling process5'6. (However, this is controversial, see also Ref. 7.) The continuing controversy over the involvement of GABA in epilepsy sug-
The first mechanically scanned laser confocal microscope was built at Yale in the early 1970s 2, for which a US Patent was awarded 3, as a direct continuation of the work on the tandem scanning microscope 4'5 cited by Fine et aP. The first CSLM photomicrographs of histologically recognizable cells were published in 19736. M. David Egger Professorand Acting Chairman,Departmentof Anatomy, UMDNJRobert WoodJohnsonMedical School, Piscataway,NJ 08854 5635, USA.
gests that a unitary theory of seizure onset is unlikely. Charles Taylor Parke-Davis PharmaceuticalResearchDivision, 2800 Plymouth Road, Ann Arbor, MI 48105 2430, USA.
References 1 Taylor, C. P. (1988) Trends Neurosci. 11,375-378 2 Schwark, W. S. and Loescher, W. (1985) N. S. Arch. Pharmacol. 329, 367-371 3 Shin, C., Rigsbee, L. C. and McNamara, J. O. (1986) Brain Res. 398,370-374 4 Hammond, E. J. and Wilder, B. J. (1985) Gen. PharmacoL 16, 441-447 5 Morimoto, K. and Goddard, G. V. (1986) Exp. Neurol. 94, 571-584 6 Michelson, H. B. etal. (1988) Epilepsia 29,658-659 7 Tuff, L. P., Racine, R. J. and Adamec, R. (1983) Brain Res. 277, 79-90
References 1 Fine, A., Amos, W. B., Durbin, R. M. and McNaughton, P. A. (1988) Trends Neurosci. 11, 346-351 2 Davidovits, P. and Egger, M. D. (1971) Applied Optics, 10, 1615-1619 3 Davidovits, P. and Egger, M. D. (1972) US Patent No. 3643015 4 Egger, M. D. and Petran, M. (1967) Science 157, 305-307 5 Petran, M., Hadravsky, M., Egger, M. D. and Galambos, R. (1968) J, Opt. Soc. Amer. 58, 661-664 6 Davidovits, P. and Egger, M. D. (1973) Nature 244, 366-367
Order your own personal copy of TINS special issues Additional copies of the TINS October special issue 'Calcium and neuronal excitability' can be obtained at a cost of $10.00/£6.00 each*, with discounts available on orders of 10 or more copies. Payment must accompany your order, and may be made by cheque (made outto Elsevier) or by credit cards. We accept Amex, Visa and Access/Mastercard/Eu rocard. * Price vafid until December 1989.
Name ........................................................................... Address ........................................................................
Credit card number ....................................................... Issuing Bank ................................................................. Expiry date ................................................................... Signature .....................................................................
Send copies of this order form to: Trends in Neurosciences, Elsevier Publications Cambridge, 68 Hills Road, Cambridge, CB2 1LA, UK.
TINS, VoL 12, No. 1, 1989
11