Differences between Physostigmine- and Yohimbine-induced States Are Visualized in Canonical Space Constructed from EEG during Natural Sleep-wake Cycle in Rats

Although quantitative EEG parameters, such as spectral band powers, are sensitive to centrally acting drugs in dose- and time-related manners, changes of the EEG parameters are redundant. It is desirable to reduce multiple EEG parameters to a few components that can be manageable in a real space as well as be considered as parameters representing drug effects. We calculated factor loadings from normalized values of eight relative band powers (powers of 0.5, 1.0~2.0, 2.5~4.0, 4.5~5.5, 6.0~8.0, 8.5~12.0, 12.5~24.5, and 25~49.5 Hz bands expressed as ratios of the power of 0.5-49.5 Hz band) of EEG during pre-drug periods (11:00~12:00) by factor analysis and constructed a two-dimensional canonical space (reference canonical space) by canonical correlation analysis. Eight relative band powers of EEG produced by either physostigmine or yohimbine were reduced to two canonical scores in the reference canonical space. While changes of the band powers produced by physostigmine and yohimbine were too redundant to describe the difference between two drugs, locations of two drugs in the reference canonical space represented the difference between two drug's effects on EEG. Because the distance between two locations in the canonical space (Mahalanobis distance) indicates the magnitude of difference between two different sets of EEG parameters statistically, the canonical scores and the distance may be used to quantitatively and qualitatively describe the dose-dependent and time-dependent effects and also tell similarity and dissimilarity among effects. Then, the combination of power spectral analysis and statistical analysis may help to classify actions of centrally acting drugs

Effects of an ACTH 4-9 related peptide upon intracranial self stimulation and general activity in the rat

Adult male Sprague-Dawley rats were stereotactically implanted with electrodes within the anterior medial forebrain bundle: The rats were trained to respond for intracranial self-stimulation (ICS) and treated with control solution or varying doses of an ACTH 4-9 related synthetic peptide (Org 2766; H-Met(O 2 )-Glu-His-Phe- d -Lys-Phe-OH). The drug affected ICS as measured in overnight response records, with the highest dose reliably increasing the amount of responding. In a second experiment rats were similarly treated and general activity was assessed. No remarkable changes in activity were present at any tested dose. The findings corroborate previous reports suggesting ACTH-related peptides may be active in a variety of motivated tasks, but less active with respect to general activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46417/1/213_2004_Article_BF00433254.pd

Classification of neuromuscular blocking agents in a new neuromuscular preparation of the chick in vitro

A neuromuscular preparation of the chick is described: 1. 1. The sciatic nerve-tibilis anterior muscle preparation of the 2–10 days old chick fulfils all criteria of an assay preparation and differentiates between curare-like and decamethonium-like agents. 2. 2. The preparation responds to supramaximal nerve stimuli with twitches, which are of constant height during 6–8 hr. The twitch amplitude is decreased by curare-like drugs in concentrations of 0.5 μg/ml and more. This effect is dose-dependent. 3. 3. The preparation responds to the administration of decamethonium-like drugs with a slow contracture, the force and velocity of which is dose-dependent, and a decrease in the height of the twitch. The time curve of these two effects of decamethonium-like drugs is not the same. Threshold dose for contractures is about 0.1 μg/ml. 4. 4. Curare-like compounds in doses of times threshold and more antagonize or prevent the slow contractures caused by decamethonium-like drugs, dose-dependently. 5. 5. The effects are easily reversible and also reproducible in the same preparation during a day. 6. 6. A resemblance is suggested between the chick slow fibre response and the responses of the cat extra-ocular muscle and the mammalian intrafusal muscle to decamethonium-like compounds; the possibility of a presynaptic site of action apart from a post-synaptic one of the decamethonium-like drugs in the chick muscle is postulated