EFFECTS OF ELECTROMAGNETIC-FIELDS ON THE LEVELS OF BIOGENIC-AMINE METABOLITES, QUINOLINIC ACID, AND BETA-ENDORPHIN IN THE CEREBROSPINAL-FLUID OF DAIRY-COWS

Eight multiparous non-lactating pregnant Holstein cows at 198 +/- 35 d of gestation, weighing 608 +/- 24 kg, were confined to wooden metabol ic cages in an electric and magnetic field chamber with a 12:12 h ligh t:dark cycle. Subarachnoidal catheters were installed 5 d before the a ctivation of the electric and magnetic fields. The cows were exposed t o electric and magnetic fields (60 Hz, 10 kV/m and 30 mu T) continuous ly except for the feeding and cleaning time for an average of 21.44 +/ - 1.4 h per day for a period of 30 d. Cerebrospinal fluid samples were collected on three consecutive days before an exposure period of 30 d , on the last 3 d of the exposure period, and for 3 d starting 5 d aft er the exposure period. The concentrations of beta-endorphin, tryptoph an, 5-hydroxyindoleacetic acid, homovanillic acid, 3-methoxy-4-hydroxy phenylethyleneglycol and quinolinic acid in cerebrospinal fluid were d etermined. There was a significant increase in quinolinic acid, and a trend towards an increase in tryptophan, findings consistent with a we akening of the blood-brain barrier due to exposure to the electric and magnetic fields.