Registration Dossier

Diss Factsheets

Administrative data

Endpoint:
neurotoxicity, other
Remarks:
in vitro test
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Test well described but the number of replicates tested and the test substance purity are not known. There is no information about control groups.

Data source

Reference
Reference Type:
publication
Title:
Catechol: a potent and specific inhibitor of the fast potassium channel in frog primary afferent neurones
Author:
Ito I., Maeno T.
Year:
1986
Bibliographic source:
J. Physiol., 373, 115-227.

Materials and methods

Principles of method if other than guideline:
In vitro effects on ionic channels of bull-frog neurones
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Pyrocatechol
EC Number:
204-427-5
EC Name:
Pyrocatechol
Cas Number:
120-80-9
Molecular formula:
C6H6O2
IUPAC Name:
pyrocatechol
Details on test material:
Purchased from Wako, purity unknown.

Test animals

Species:
other: frog
Strain:
other: Rana catesbeiana
Sex:
not specified

Administration / exposure

Route of administration:
other: in vitro test
Vehicle:
other: solutions containg different cations
Details on exposure:
The experiments were carried out on the isolated dorsal root ganglion cells of the American bull-frog (Rana catesbeiana).
- Effect of catechol on the action potential: Enzymatically cleaned neurones were perfused with appropriate external and internal solutions (pH 7.4). Catechol concentrations were 1.1 - 550 mg/L. 
Experiments were carried out at a room temperature of 18-20°C.  The duration of the action potential was determined using a single-electrode clamp system at the half-maximum amplitude. The action potentials were elicited by currents of 0.5-0.8 nA.
To determine the exact mode of action of catechol, its effects on Na+, Ca2+, and K+ currents were analysed in detail.
Control animals:
no

Results and discussion

Results of examinations

Details on results:
Result: positive
- Catechol was effective when applied on the external surface of the cell membrane. 110 mg/L catechol in the external solution increased the duration of action potential almost 2-fold, while the effects of its internal perfusion were small. 
The ED50 for the prolongation of action potential was estimated from Lineweaver-Burk and Eadie-Hofstee plots of the data (55-550 mg/L catechol) to be about 71.6 mg/L.
- Catechol was found to inhibit rather specifically the fast K+ current. Ca2+, Na+ and slow K+ currents were not affected.

Applicant's summary and conclusion