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Current Research of Department of Cellular Membranology


Ischemia model | Drug Screening | Jumping Table | Publications

PHARMACOLOGICAL STUDIES ON IONIC CHANNELS AND RECEPTORS

Immediately available types of neurons acutely isolated from rats at the age of 1-4 weeks:

  • pyramidal neurons from hippocampus and cortex;
  • Purkinje neurons;
  • Spinal dorsal horn neurons;
  • primary sensory neurons (DRG, trigeminal etc.).
  • Isolation of neurons from any nervous tissue, central or peripheral, can be developed within 4-6 weeks upon request.

Voltage-operated channels available for pharmacological examination:

  • Na+ channels, TTX-sensitive or insensitive;
    protocols are developed to determine voltage- and/or use-dependent modes of drug action;
  • Ca2+ channels;
    by using pharmacological separation virtually all known types of Ca channels, namely L, N, P/Q and T, can be studied separately; e.g. N-channels are measured in hippocampal neurons under dihydropyridine + Aga IVA toxin);
  • K+ channels (A, DR etc.).

Receptor-operated channels studied in conditions of rapid application of substances (computerised high throughput concentration clamp):

  • AMPA- and NMDA-receptor operated channels;
  • GABA- and glycine-operated channels;
  • Various P2X channels in primary sensory neurons and in central neurons;
  • Various ASICs in primary sensory neurons and in central neurons;
  • Vanilloid receptors;
  • ACh operated channels.


Ischemia model | Drug Screening | Jumping Table | Publications

SCREENING FACILITIES AND PHARMACOLOGICAL PROFILING

We have 6 fully automated set-ups for patch clamp screening. Dozens of substances can be rapidly (within 10 ms) applied to a single cell in the concentration clamp mode. This ensures minimal use of the the tested substances and possibility of studying the fastest receptor/channel mechanisms in the concentration clamp mode. The function of this set-up (patented in US) is demonstrated at WMV ~450KB (HTTP). Principal scheme movie WMV 9 ~430KB (HTTP). DivX ~610KB (HTTP),

Important feature: a given substance can be tested within a few days on its effect against all major receptors/channels in the cells from any desired nerve tissue.

The contract research usually includes not only screening, but also physiological/biophysical analysis of the observed phenomenology. The Reference list below features the research performed in collaboration with several pharmacological companies.


Ischemia model | Drug Screening | Jumping Table | Publications

GLOBAL ISCHEMIA INDUCED BY DECAPITATION: A SIMPLE MODEL FOR QUICK ELECTROPHYSIOLOGICAL EVALUATION OF NEUROPROTECTORS.

This simple model allows one to perform easy and quick evaluation of neuroprotective drugs. The ischemic damage is created as follows: the animal (adult rat) is decapitated and its head with intact non-perfused brain is kept in a thermostatically controlled moist chamber for 90-120 min at 30o C. Then the brain is removed and slices of hippocampus are prepared in the usual way and kept oxygenated. Responses of the CA1 area to both orthodromic and antidromic stimulation of the CA1 area are greatly reduced after this procedure. The mean amplitude of the maximum post-ischemic population spike was 0.9 ± 0.1 mV. About 40 % of the slices completely lost excitability. The mean amplitude of maximum population spike obtained in control conditions (immediate preparation of slices following decapitation) was 5.1 ± 0.7. We have found that the action of neuroprotectors is clearly manifested in this model. For example, when MK-801 was injected intraperitonealy 15 min before decapitation, the mean amplitude of post-ischemic population spike was 4.5 ± 0.7 mV ( 89 % of control). The ED50 for this action of MK-801 was 0.2 mg/kg. The sequence of potencies of the tested neuroprotectors was as follows: MK-801 > NBQX > nifedipine. The model is also sensitive to neuroprotectors that are not channel blockers (ascorbic acid). It allows one to give yes-or-no answer for 3-4 drugs/set-up/day and to obtain the dose-response relationship for 1 drug /set-up/ week.

The work was supported in part by the grant from Howard Hughes Medical Institute (73195-548001), from Soros International Science Foundation (U51000) and from INTAS (94-849).


Ischemia model | Drug Screening | Jumping Table | Publications

SELECTED PUBLICATIONS IN COLLABORATION WITH PHARMACEUTICAL COMPANIES

  1. Chatterjee SS, Kondratskaya EL and Krishtal OA (2003) Structure-activity studies with Ginkgo biloba extract constituents as receptor-gated chloride channel blockers and modulators. Pharmacopsychiatry(.36):68-77
  2. Kondratskaya EL, Lishko PV, Chatterjee SS, Krishtal OA (2002) BN52021, a platelet activating factor antagonist, is a selective blocker of glycine-gated chloride channel. Neurochem.Int. 40:647-653
  3. Krishtal O, Kirichok Y, Tsintsadze T, Lozovaya N, Loesel W, Arndts D (2001) New channel blocker BIIA388CL blocks delayed rectifier, but not A-type potassium current in central neurons. Neuropharmacology 40:233-241
  4. Lalo UV, Pankratov YV, Arndts D, Krishtal OA (2001) Omega-conotoxin GVIA potently inhibits the currents mediated by P2X receptors in rat DRG neurons. Brain Res.Bull. 54:507-512
  5. Chatterjee S., Filippov V., Lishko P., Maximyuk O., Noldner M., Krishtal O. (1999) Hyperforin attenuates various ionic conductance mechanisms in the isolated hippocampal neurons of rat. Life Sci. -V 65, - P. 2395-2405.
  6. Lishko PV, Maximyuk OP, Chatterjee SS, Noldner M, Krishtal OA (1998) The putative cognitive enhancer KA-672.HCl is an uncompetitive voltage-dependent NMDA receptor antagonist. Neuroreport. 9:4193-4197
  7. Magura EI, Kopanitsa MV, Gleitz J, Peters T, Krishtal OA (1997) Kava extract ingredients, (+)-methysticin and (+/-)-kavain inhibit voltage-operated Na(+)-channels in rat CA1 hippocampal neurons. Neuroscience 81:345-351
  8. Panchenko VA, Pintor J, Tsyndrenko AY, Miras-Portugal MT, Krishtal OA (1996) Diadenosine polyphosphates selectively potentiate N-type Ca2+ channels in rat central neurons. Neuroscience 70:353-360
  9. Parsons CG, Panchenko VA, Pinchenko VO, Tsyndrenko AY, Krishtal OA (1996) Comparative patch-clamp studies with freshly dissociated rat hippocampal and striatal neurons on the NMDA receptor antagonistic effects of amantadine and memantine. Eur.J.Neurosci. 8:446-454
  10. Kiskin NI, Chizhmakov IV, Tsyndrenko AY, Mueller AL, Jackson H, Krishtal OA (1992) A highly potent and selective N-methyl-D-aspartate receptor antagonist from the venom of the Agelenopsis aperta spider. Neuroscience 51:11-18


Ischemia model | Drug Screening | Jumping Table | Publications

Updated: January 13, 2004.
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