Pyrocatechol

Neurotoxicity

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:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

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

Test material information

Constituent 1

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

Conclusions:

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.