Effects of chronic nicotine administration and age on various neurotransmitters and associated enzymes in male Fischer-344 rats

Cerebral metabolic and behavioral effects of acutely administered nicotine were measured in rats in relation to dose. Nicotine 0.1, 1, or 10 mg/kg or vehicle was administered intraperitoneally to 3-month-old male Fischer-344 rats that had been pretreated with hexamethonium bromide 5 mg/kg i.p. to reduce peripheral autonomic effects. Regional CMRglc (rCMRglc) values were measured, using the quantitative autoradiographic [14C]-2-deoxy-d-glucose method, in 71 brain regions, beginning 3 min after nicotine or vehicle administration. Intensity of body tremor, scored by a blinded rater, was dose related and peaked at 3 min after nicotine injection. rCMRglc rose in a dose-related manner: Nicotine 0.1 mg/kg had no significant effect in any region, whereas 1 mg/kg elevated rCMRglc significantly in 21 regions (mean rise 20%) and 10 mg/kg produced generalized (56 regions) and greater (mean rise 50%) increases in rCMRglc. Nicotine 1 mg/kg activated thalamic nuclei, cerebellum, geniculate nuclei, superior colliculus, median raphe, reticular formation, and the habenulointerpeduncular pathway, but was without effect in the telencephalon. Effects of nicotine in the hindbrain were related anatomically to reported distributions of [3H]nicotine and [3H]acetylcholine but not [125I]α-bungarotoxin binding sites, implying that the former ligands label functional nicotine receptors. The pattern of change in rCMRglc after nicotine administration suggests that its cognitive effects in humans are due to augmented arousal/attention and visual processing rather than to direct neocortical or hippocampal activation.

Download Full-text

Toxic effects of inhaled DMMP on the kidneys of Fischer-344 rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128687 ◽

1987 ◽

Vol 45 ◽

pp. 880-881

Author(s):

D.R. Mattie ◽

C.J. Hixson

Keyword(s):

Left Kidney ◽

Inhalation Exposure ◽

Electron Microscopic Examination ◽

Exposure Period ◽

Male Rats ◽

Continuous Exposure ◽

Fischer 344 Rats ◽

Electron Microscopic ◽

Thin Sections ◽

Fischer 344

Dimethylmethylphosphonate (DMMP) is a simple organophosphate used industrially as a flame retardant and to lower viscosity in polyester and epoxy resins. The military considered the use of DMMP as a nerve gas simulant. Since military use of DMMP involved exposure by inhalation, there was a need for a subchronic inhalation exposure to DMMP to fully investigate its toxic potential.Male Fischer-344 rats were exposed to 25 ppm or 250 ppm DMMP vapor on a continuous basis for 90 days. An equal number of control rats were sham-exposed. Following the 90-day continuous exposure period, 15 male rats were sacrificed from each group. Two rats from each group had the left kidney perfused for electron microscopic examination. The kidneys were perfused from a height of 150 cm water with 1% glutaraldehyde in Sorensen's 0.1M phosphate buffer pH 7.2. An additional kidney was taken from a rat in each group and fixed by immersion in 2.5% glutaraldehyde and 2% paraformaldehyde in 0.1M cacodylate buffer pH 7.4. A portion of the 9 kidneys collected for electron microscopy were processed into Epon 812. Thin sections, stained with uranyl acetate and lead citrate, were examined with a JEOL 100B Transmission Electron Microscope. Microvilli height was measured on photographs of the cells of proximal tubules. This data, along with morphologic features of the cells, allows the proximal convoluted tubules (PCT) to be identified as being S1, S2, or S3 segment PCT.

Download Full-text

Ultrastructure of rat alveolar macrophages activated in situ by poly:IC

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128158 ◽

1987 ◽

Vol 45 ◽

pp. 768-769

Author(s):

A. M. Klinkner ◽

R. A. Weiss ◽

A. Kelley ◽

P. J. Bugelski

Keyword(s):

Venous Blood ◽

Intratracheal Instillation ◽

Buffy Coat ◽

Fischer 344 Rats ◽

Blood Monocytes ◽

Fischer 344 ◽

Polyinosinic:Polycytidylic Acid ◽

Macrophage Activator ◽

Endogenous Peroxidase

Polyinosinic:polycytidylic acid is an inducer of interferon and a macrophage activator. We have found that intratracheal instillation of polyI:C (IT-pI:C) activates rat bronchoalveolar lavage cells (BAL) for a variety of functions. Examination of Giemsa stained, cytocentrifuge preparations showed that IT-pI:C induced a population of BAL not seen in resident BAL. The morphology of these cells suggested that they might be derived from blood monocytes. To test this hypothesis we have examined several populations of macrophages that had been stained for endogenous peroxidase activity as a marker of cells derived from the monocyte-macrophage lineage.Macrophages were obtained from Fischer 344 rats. Peritoneal exudate cells (PEC) were collected by lavage 4 days after i.p. injection of 20 ml 3% thioglycolate. Buffy coat monocytes were separated from venous blood from naive rats.

Download Full-text