Tin sulphate

Neurotoxicity

Administrative data

Endpoint:

neurotoxicity

Remarks:

other: acute experiment in ganglion of mollusk

Type of information:

experimental study

Adequacy of study:

other information

Study period:

1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: no glp, no guideline, but well documented

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2000

Report Date:

1998

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Methods
The effects of SnCl_2 and Sn8CH_3)_2 on the acetylcholine-activated currents were studied in
identified neurons of the pulmonate mollusk Lymnaea stagnalis, using a two microelectrode
membrane patential clamping method and intracellular dialysis in conditions of fixed potential
and ion concentrations.
Adult animals were colleceted in Lake Kish-Balaton and kept in aquarium at a temperature of
20-22°C. Experiments were conducted either on neurons in whole gaglion preperations or after
isolation of induvidula nerve cells.
Ganglia were prepared and identified neurons were isolated. Experiments using the two micro-
electrode membrane potential clamping technique, dissected ganglia were incubated in physiological
saline containing 0.1% protease for 5 min at room temperature. Connective tissue was then
removed and ganglia were washed in physiological saline and stored in the refigerator at 4°C
for 1 -2 h.
Experiments were performed using identified neurons RPcD1, VV12, VDC and RPaD1. Standard solution
contained 44mM NaCl, 1.7 mM KCl, 4 mM CaCl_2, 10 mM HEPES, pH 7.4. Solution for intracellular
dialysis consists of 43.5 mM KOH, 20 mM KCl, 10 mM EGTA, 2.5 mM HEPES, pH 7.3. This membrane
potential clamping method used a Dagan 8500 amplifier and an Axopatch-1D amplifier. Two
independent mircolecetrodes filled with 2.5 M potassium acetate and 25 mM KCl were insered in
neurons. Potential steps and data analyis were carried out using an A/D-D/A concerter card and
a standalone program. Chemical compounds were obtained from Sigma and Reanal. All experiments
were conduceted at room temperature (20-22°C). Acetylcholine was applied by mircoperfusion or
by replacing the whole solution for 12-16 sec with intervals 4-5 m in.

GLP compliance:

no

Limit test:

no

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

solid - liquid: suspension

Details on test material:

-

Test animals

Species:

other: mollusk

Strain:

other: Lymnaea stagnalis

Sex:

not specified

Administration / exposure

Route of administration:

other: not relevant, see method

Vehicle:

other: not relevant, see method

Analytical verification of doses or concentrations:

not specified

Frequency of treatment:

see method

Doses / concentrations

Remarks:

Doses / Concentrations:
see method
Basis:
other: see method

No. of animals per sex per dose:

see method

Control animals:

yes

Results and discussion

Effect levels

Dose descriptor:

other: inhibition of sodium channels

Effect level:

25 other: µM

Based on:

test mat.

Sex:

not specified

Remarks on result:

other:

Any other information on results incl. tables

see publication

Applicant's summary and conclusion

Conclusions:

Sn+2 inhibits reversible the sodiom channels in ganglion

Executive summary:

In isolated single neurone or in whole ganglia preparation, SnCl2 caused a decrease in the acetylcholine-induced inward current in a dose-dependent way. Threshold concentration was 0.1 mkM and saturated at 5 mkM SnCl2. After 10-min. pre-treatment with SnCl2 the effect was more obvious (by 20%) than after 3-min pre-treatment. Sn(CH3)2 decreased the amplitude of Ach-induced current similarly to the inorganic Sn. The effect of Sn(CH3)2 was irreversible. The findings support earlier data that the agonist-activated channels are important targets for toxic metals. Direct action upon neuronal membrane seems to be an important event in modulation of synaptic transmission.