The localization of receptor binding sites in the substantia nigra and striatum of the rat

Neurotransmitter receptor binding of 5 ligands was examined in the striatum, substantia nigra (SN) and frontal cortex of rats which had received either unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal pathway (NSP) or unilateral kainic acid lesions of the striatum. 6-OHDA lesions of the NSP significantly reduced [3H]dihydroalprenolol ([3H]DHA) and [3H]naloxone ([3H]Nal) binding by 31% and 28% respectively, in the denervated striatum compared to the contralateral side. Scatchard analysis revealed that the alteration in [3H]DHA binding was not due to a change in the affinity of the beta-adrenergic receptor for [3H]DHA. In marked contrast to these changes in the striatum, destruction of the NSP resulted in a significant increase in [3H]DHA and [3H]Nal binding by 44% and 26%, respectively, in the frontal cortex of the lesioned compared to the control side. 6-OHDA lesions in the NSP did not alter striatal receptor binding for [3H]quinuclidinyl benzilate ([3H]QNB), [3H]muscimol ([3H]Mus) or [3H]flunitrazepam ([3H]Flu). Similarily, intrastriatal kainic acid injections did not alter striatal receptor binding for [3H]Nal, [3H]Flu or [3H]Mus. Of the various receptor densities measured in the SN after the above lesions the only alteration observed was a 43% increase in [3H]Flu binding following 6-OHDA lesions of the NSP. Scatchard analysis indicated no change in the affinity of the benzodiazepine receptor for [3H]Flu. 6-OHDA lesions of the NSP did not alter [13H]QNB or [3H]Nal binding in the SN. Striatal kainic acid lesions did not alter nigral [3H]QNB or [3H]Flu binding. The results are discussed in terms of neurotransmitter localization and plasticity within the striatum, SN and frontal cortex.     

In vivo incorporation of dietary ( 14 C)cholesterol in rat serum lipoproteins and transfers in connective tissue

In rats in isotopically steady state, the incorporation of dietary [¹⁴C]cholesterol in α- and β-lipoproteins is very different. β-Lipoproteins incorporate 30 times more of dietary cholesterol than α-lipoproteins. Most of the cholesterol in several connective tissues (skin, aorta, subcutaneous, polyvinyl sponge connective tissues) derives from β-lipoproteins. The turnover of cholesterol in sponge tissue is 2-fold higher than in the aorta, and 4-fold higher than in skin.     

A case-control study of pesticides and fetal death due to congenital anomalies

We examined the association between late fetal death due to congenital anomalies (73 cases, 611 controls) and maternal residential proximity to pesticide applications in ten California counties. A statewide database of all applications of restricted pesticides was linked to maternal address to determine daily exposure status. We examined five pesticide chemical classes. The odds ratios from logistic regression models, adjusted for maternal age and county, showed a consistent pattern with respect to timing of exposure; the largest risks for fetal death due to congenital anomalies were from pesticide exposure during the 3rd-8th weeks of pregnancy. For exposure either in the square mile of the maternal residence or in one of the adjacent 8 square miles, odds ratios ranged from 1.4 (95% confidence interval = 0.8-2.4) for phosphates, carbamates, and endocrine disruptors to 2.2 (95% confidence interval = 1.3-3.9) for halogenated hydrocarbons. Similar odds ratios were observed when a more restrictive definition of nonexposure (not exposed to any of the five pesticide classes during the 3rd-8th weeks of pregnancy) was used. The odds ratios for all pesticide classes increased when exposure occurred within the same square mile of maternal residence.