Featured Research

from universities, journals, and other organizations

Toxin Combo Common In Fish Appears Capable Of Impairing Motor Skills

Date:
March 3, 2004
Source:
University Of Illinois At Urbana-Champaign
Summary:
Pups of female rats exposed to a combination of polychlorinated biphenyls (PCBs) and methylmercury (MeHg) slip and fall more often trying to maneuver on a rotating rod than do pups from non-exposed moms, scientists say.

CHAMPAIGN, Ill. -- Pups of female rats exposed to a combination of polychlorinated biphenyls (PCBs) and methylmercury (MeHg) slip and fall more often trying to maneuver on a rotating rod than do pups from non-exposed moms, scientists say.

Related Articles


The findings, published in the February issue of the journal Toxicological Sciences, come from a study focusing on the effects of combined exposure of the two commonly found environmental contaminants on motor function driven by the cerebellum.

"Because people are exposed to these toxicants by eating fish taken from ecosystems where these chemicals accumulate, our findings suggest that we should seriously consider the possible impact of their additive toxic effects on human health," said Susan L. Schantz, a professor of veterinary biosciences at the University of Illinois at Urbana-Champaign.

Previous laboratory studies had suggested that the two chemicals act together to impair nervous system function. A study in February's issue of the Journal of Pediatrics found that exposure to methylmercury causes heart damage and impairs brain growth.

The new study -- pursued as part of the doctoral dissertation by Schantz's graduate student Cindy S. Roegge -- shows that motor skills were not significantly affected by methylmercury exposure alone, but when paired with PCBs the combined effect during development dramatically impacted the pups' skills in one of three motor tests.

The research was done for the federally funded FRIENDS Children's Environmental Health Center, a five-institution consortium based at the College of Veterinary Medicine at Illinois. Schantz is director of FRIENDS (Fox River Environment and Diet Study), which is studying the effects of exposure to toxicants in fish being eaten in large quantities by Laotian and Hmong refugees in Green Bay and Appleton, Wis.

In the study, female rats were exposed to just PCBs or just MeHg or to both chemicals, beginning four weeks before breeding and ending when their pups were weaned. None of the female rats showed signs of toxicity, said Schantz, who also is a professor in the Neuroscience Program and psychology department at Illinois.

At birth, the pups of mothers exposed to methylmercury alone did not differ in weight from the control group. The birth weight of pups whose mothers had been exposed to just PCBs or both chemicals was slightly, but significantly, less than the control animals.

At weaning, the weight of pups exposed to PCBs was as much as 11 percent below that of control animals, while the pups in the PCB-MeHg exposure group weighed as much as 15 percent less than controls.

Two months later, one male and female pup from each litter were tested for the next four weeks on their abilities to navigate vertical ropes, parallel bars and various speeds of rotating rods. At the end, female pups whose mothers had been exposed to MeHg were slightly impaired on the rope-climbing test, while their male counterparts actually had less hind-limb slips on the parallel bars. Overall, the results of the MeHg-exposed pups were not significantly different than that of the control animals.

However, on the rotating rods the impact of exposure to both PCBs and methylmercury became clear. As the speed of the rods exceeded 25 rpm, the pups, regardless of sex, that were exposed to both toxicants during their mothers' pregnancies slipped significantly more often than their control counterparts. Exposure to either of the chemicals alone did not significantly impact performance.

However, Schantz said, the tests showed that PCB exposure contributed more than did the methylmercury to the pups' deficits, although the low dosage of MeHg used in the study (1.20 milligrams compared with the 2 to 18 mg used in previous studies of motor skills) may explain why.

It could be, the researchers wrote, that the chemicals have independent mechanisms of toxicity or they each act by means of the same mechanism but with greater impact together.

In addition to Schantz and Roegge, the other contributors were Illinois doctoral students Victor C. Wang and Brian E. Powers; Sherilyn Villareal, a visiting research specialist in veterinary biosciences; William T. Greenough, a professor of psychology and cell and structural biology at the Beckman Institute for Advanced Science and Technology at Illinois; and Anna Y. Klintsova, a psychology professor at Binghamton University in New York who formerly worked with Greenough at the Beckman Institute.

The U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences funded the study. The two agencies also fund the FRIENDS Children's Environmental Health Center.


Story Source:

The above story is based on materials provided by University Of Illinois At Urbana-Champaign. Note: Materials may be edited for content and length.


Cite This Page:

University Of Illinois At Urbana-Champaign. "Toxin Combo Common In Fish Appears Capable Of Impairing Motor Skills." ScienceDaily. ScienceDaily, 3 March 2004. <www.sciencedaily.com/releases/2004/03/040302075817.htm>.
University Of Illinois At Urbana-Champaign. (2004, March 3). Toxin Combo Common In Fish Appears Capable Of Impairing Motor Skills. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2004/03/040302075817.htm
University Of Illinois At Urbana-Champaign. "Toxin Combo Common In Fish Appears Capable Of Impairing Motor Skills." ScienceDaily. www.sciencedaily.com/releases/2004/03/040302075817.htm (accessed October 25, 2014).

Share This



More Plants & Animals News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins