Herbert Wiegand

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Chronic lead exposure during brain development is known to affect functions of the central nervous system. We exposed rats chronically to low levels of lead at different developmental stages in order to determine the most sensitive periods of exposure. Active avoidance learning and hippocampal long-term potentiation were tested in the same animals. If the(More)
In order to assess the degree of thallium exposure in a population living around a thallium emitting cement plant in a small city in North-West Germany thallium levels in 24 h urine samples of 1,265 subjects and in hair samples of 1,163 subjects were determined. Urinary thallium levels in two groups of subjects living in an urban and a rural area of West(More)
Using the whole cell patch-clamp technique, calcium (Ca) channel currents from cultured medial neurosecretory cells (MNSCs) of Locusta migratoria (Rössler and Bickmeyer, 1993) were investigated. The calcium channel blocker omega AGA toxin IVA (AGA IVA) blocks a fraction of these calcium channel currents in approximately 30% of MNSCs, without a shift in the(More)
Within a larger comparative environmental health screening program in East and West Germany we investigated functions of the developing visual system in field experiments in a total of 384 children living in three different areas. Visual functions were assessed neurophysiologically by visual-evoked potentials (VEPs) and psychophysically by measuring the(More)
From 1979 to 1981, several medical surveys were carried out among a population living in the vicinity of a cement plant that emitted dust containing thallium until August, 1979. Air, soil, plants, and domestic animals in the area were contaminated by thallium and this led to an increased intake of thallium in the population, mainly due to the consumption of(More)
Orthodromically evoked field potentials were recorded in the CA1 region of hippocampal slices while perfusing the slices with media containing lead acetate. High-frequency stimulation (HFS) was applied to the stratum radiatum during lead perfusion. In half of the slices investigated, HFS resulted in an initial increase of the evoked responses which decayed(More)
Calcium channel currents of bovine chromaffin cells are blocked by the bis-benzyl-isoquinoline alkaloid tetrandrine, which is isolated from the roots of the chinese medical herb Stephania tetrandra. The half-maximal inhibition (IC50) occurred at a concentration of about 10 microM. Bovine chromaffin cells possess no low-voltage-activated, but different types(More)
Rats were exposed prenatally to the coplanar congener 3,3',4,4'-tetrachlorobiphenyl (TCB). The amount of long-term potentiation (LTP) was measured in slices from the visual cortex and hippocampus of the adult males as well as of controls. While in the cortical slices from the controls a stable LTP could be induced, LTP was inhibited in the TCB-exposed rats.(More)
Tetrandrine, a bis-benzyl-isoquinoline alkaloid from the roots of Stefania Tetranda blocks calcium currents in cultured neurones of the spinal cord of foetal mice. The concentration of half-maximal effect (Kd) measured 100 ms after the beginning of a depolarizing pulse (-80 mV-0 mV) is 8 microM. While high- and low-voltage activated (HVA, LVA) currents are(More)
The neurotoxic potential of polychlorinated biphenyls (PCBs) depends on the structure of the congener as well as on the age of the exposure. We exposed rats prenatally to a coplanar congener (PCB-77) or to a non-coplanar congener (PCB-47) and measured the amount of long-term potentiation (LTP) at postnatal days 11-19 in the visual cortex and hippocampus.(More)