Registration Dossier

Administrative data

Endpoint:
neurotoxicity
Adequacy of study:
other information
Reliability:
2 (reliable with restrictions)

Data source

Reference
Title:
No information
Author:
Banik, S and Lahiri, T (2005) Decrease in brain serotonin|level and short term memory loss in mice: a preliminary|study. Environ. Toxicol. Pharmacol. 19, 367-370.

Materials and methods

Test material

Reference
Name:
Unnamed
Type:
Constituent

Results and discussion

Any other information on results incl. tables

Brain serotonin (ug/g tissue) was decreased significantly in a dose- and time-dependent manner following benzene treatment for 15 or 30 d:

  

-- 166 mg/l --

-- 332 mg/l --

 

0

15 d

30 d

15 d

30 d

Raphe

0.71

0.19*

0.11*

0.11*

0.07*

Hypothalamus

1.2

0.48*

0.23*

0.26*

0.15*

Caudate putamen

0.36

0.06*

0.02*

0.09*

0.01*

* P0.05


Benzene-treated mice exhibited a significant, reversible decrease in step-through latency when compared with negative controls:


-- Relative latency --

 

Benzene

(mg/l)

  

166

332

+ve control

440

-ve control

100

Treated:

48 hr

180

150

7 d

140

110

15 d

95

80

30 d

90

90

(Approx. values, obtained by interpolation from graphical data)


Comment: no statistical analysis performed on these data; values for treated animals appear to be comparable to untreated controls by 15 d post-exposure.

Applicant's summary and conclusion

Conclusions:
The results suggest that repeated (sub-acute) oral exposure to relatively high concentrations of benzene is associated with altered levels of 5-HT is selected areas of the brain (hypothalamus, raphe and caudate putamen), with reversible deficits in passive avoidance learning in mice.