PubMed Health⌕ Search

Biomedical subjects

P Ramm

Publications and source records attributed to P Ramm.

6 recordsLinked to original sources
PubMed1990

Rates of cerebral protein synthesis are linked to slow wave sleep in the rat.

Using L-[1-14C]leucine autoradiography, rates of cerebral and local cerebral protein synthesis were studied during wakefulness, slow wave sleep (SWS) and REM sleep in the rat. In the cerebrum as a whole, the rate at which labelled leucine was incorporated into tissues was positively correlated with the occurrence of slow wave sleep. We failed to observe a significant correlation of protein synthesis rate with either wakefulness or REM sleep. As in the cerebrum as a whole, most discrete brain regions showed moderate positive correlations between the occurrence of SWS and rates of protein synthesis. There were no brain regions in which rates of protein synthesis showed striking correlations with sleep-wake states. Thus, the occurrence of SWS is associated with higher rates of protein synthesis throughout the brain. These data suggest that SWS sleep favors the restoration of cerebral proteins.

Animals↗
PubMed1987

Effects of extinction, pimozide, SCH 23390, and metoclopramide on food-rewarded operant responding of rats.

The similarity in the pattern of responding produced by extinction and dopamine (DA) receptor blockers has led to the suggestion that DA neurons may participate in the usual effects of reward on behaviour. The purpose of the present study was to evaluate the effect of receptor-subtype specific DA antagonists on food-rewarded operant responding. Rats were trained to lever press for food on a variable interval 30-s schedule. They then received one of the following treatments prior to testing on the next 5 days: saline, nonreinforcement, the DA receptor blocker pimozide (0.5 or 1.0 mg/kg), the D1 receptor blocker SCH 23390 (0.01, 0.05, 0.1 mg/kg), and the D2 receptor blocker metoclopramide (1.0, 5.0, 10.0 mg/kg). Nonreinforcement resulted in both intra- and intersession declines in responding. The drugs produced dose-dependent decreases in overall responding. Additionally, both doses of pimozide and the higher doses of SCH 23390 and metoclopramide altered intrasession patterns of responding when compared to saline, with their greatest effect being in the latter portion of the session. Intersession declines were seen with the highest doses of SCH 23390 and metoclopramide and control studies showed that these declines could not be attributed to a buildup of the drug with repeated dosing. It was concluded that both D1 and D2 receptors participate in the control of behaviour by reward.

Animals↗
PubMed1986

Cerebral and local cerebral metabolism in the cat during slow wave and REM sleep.

[14C]2-deoxyglucose autoradiography was used to show cerebral and regional cerebral metabolism during slow-wave sleep (SWS) and rapid-eye-movement sleep (REM) in the cat. Lower levels of mean cerebral metabolism, reflecting cerebral energy conservation, were associated with SWS. A clear link between REM and mean cerebral metabolism was not observed. At the regional level, SWS was associated with markedly low metabolism in thalamic sensory relays and in cortex. REM was associated with relatively low metabolism in the cerebellum, but with relatively high metabolism in the hippocampus, and in some 'motor' regions including the trigeminal and red nuclei. Thus, SWS was linked to cerebral energy conservation and to particularly low levels of functional activity in cortical and sub-cortical sensory regions. REM was unlike SWS in that: REM did not appear to be strongly linked to cerebral energy conservation; REM was linked to metabolism in fewer brain regions than was SWS; and most REM-linked regions exhibited relatively high levels of metabolism. In addition, while SWS was most clearly associated with functional activity in sensory regions, REM was linked to functional activity in a small number of limbic and motor regions. In sum, SWS and REM are associated with distinctive cerebral metabolic and functional states.

Animals↗
PubMedDate not supplied

Recent trends in receptor analysis techniques and instrumentation.

Receptor autoradiography allows visualization of receptor binding sites at the regional or light microscopic level. Receptor autoradiography is a mature methodology, in widespread use. It is also a dynamic and expanding methodology, benefiting constantly from the introduction of new techniques and instrumentation. In particular, receptor autoradiography has taken advantage of image analysis instrumentation to provide efficient spatial mapping of receptor populations and their pharmacological characteristics. A major contribution to the understanding of receptors has come from the recent cloning of the genes coding for many of these receptors. This has allowed the use of in situ hybridization to demonstrate the cells expressing mRNA coding for specific receptor subtypes. The result is that many receptor populations, previously thought to be homogeneous, are shown to be composed of several subtypes. As a consequence, the distribution of many receptors requires re-examination, which is aided by the development of new and more selective ligands. With the incorporation of techniques from molecular biology into receptor autoradiography, the demands upon image analysis instruments have expanded. Over the past decade, densitometric image analysers have attained a high level of sophistication for classical receptor autoradiography. However, to serve the needs of today's receptor laboratory, an image analyser must be equally capable in regional densitometry, in counting and spatial mapping of grain and/or cell locations at the microscopic level, and in analysing electrophoresis gels. Advances in image analysis hardware and software are keeping pace with the requirements of receptor laboratories.

Animals↗
PubMedDate not supplied

Image analyzers for bioscience applications.

Image analysis systems are becoming more sophosticated, less costly, and very common in research laboratories. Therefore, the bioscience researcher is faced with a bewildering array of choices in establishing an image analysis facility. Critical components and characteristics of commercial image analyzers are discussed. State-of-the-art systems feature a graphical user interface, a powerful operating system (e.g., Microsoft OS/2), 1000 line image acquisition, processing and display, true color imaging, and very flexible scanner interfaces. Such systems are best suited to technically difficult applications, such as ratio fluorescence, or to automated analysis of anatomical features, particularly in stained material. Less powerful image analyzers offer medium resolution, and typically work with monochrome data acquired from video cameras. Such systems are suitable for many bioscience applications, including quantitative autoradiography and routine morphometry.

Analog-Digital Conversion↗