The Impact of Cannabidiol on the Induction of Isoflurane Anesthesia and Recovery in Wistar Rats.

Background: Beside others, neuroinhibitory and sedative effects of CBD were documented. Aim and Methods: The aim of the study was to assess the dose-related effects of CBD premedication on the course of isoflurane anesthesia. Wistar rats were pretreated with different doses of CBD 1 h before isoflurane anesthesia. In the pretreatment, animals were given CBD at doses of 100, 20, 10, or 2 mg kg-1. Before the fifth (control) anesthesia, the animals were given only mid-chain triglyceride oil, which served as a solvent in the CBD formulation. The induction time was determined, and on awakening, the time to appearance of the flexion reflex and the recovery from anesthesia were determined. Results: Statistical analysis showed a significantly shorter induction time if animals were pretreated with 20 mg kg-1 CBD. In addition, pretreatment with 100 mg kg-1 CBD resulted in a prolonged induction time, while on awakening, delayed appearance of reflexes and prolonged recovery from anesthesia compared to pretreatment with 20 mg kg-1 CBD were observed. Conclusions: The results indicate that the influence of CBD on the course of isoflurane anesthesia depends on the dose and can reduce the induction time. Although this study was performed in laboratory rats, in clinical practice, these data should be considered when CBD-treated patients undergo isoflurane anesthesia.

Electron Paramagnetic Resonance Gives Evidence for the Presence of Type 1 Gonadotropin-Releasing Hormone Receptor (GnRH-R) in Subdomains of Lipid Rafts.

This study investigated the effect of type 1 gonadotropin releasing hormone receptor (GnRH-R) localization within lipid rafts on the properties of plasma membrane (PM) nanodomain structure. Confocal microscopy revealed colocalization of PM-localized GnRH-R with GM1-enriched raft-like PM subdomains. Electron paramagnetic resonance spectroscopy (EPR) of a membrane-partitioned spin probe was then used to study PM fluidity of immortalized pituitary gonadotrope cell line αT3-1 and HEK-293 cells stably expressing GnRH-R and compared it with their corresponding controls (αT4 and HEK-293 cells). Computer-assisted interpretation of EPR spectra revealed three modes of spin probe movement reflecting the properties of three types of PM nanodomains. Domains with an intermediate order parameter (domain 2) were the most affected by the presence of the GnRH-Rs, which increased PM ordering (order parameter (S)) and rotational mobility of PM lipids (decreased rotational correlation time (τc)). Depletion of cholesterol by methyl-ß-cyclodextrin (methyl-ß-CD) inhibited agonist-induced GnRH-R internalization and intracellular Ca2+ activity and resulted in an overall reduction in PM order; an observation further supported by molecular dynamics (MD) simulations of model membrane systems. This study provides evidence that GnRH-R PM localization may be related to a subdomain of lipid rafts that has lower PM ordering, suggesting lateral heterogeneity within lipid raft domains.

Age-Dependent Expression of MyHC Isoforms and Lipid Metabolism-Related Genes in the Longissimus Dorsi Muscle of Wild and Domestic Pigs.

This study aimed to compare age-dependent changes in the relative expression of genes encoding myosin heavy chain (MyHC) isoforms and selected lipid metabolism-related genes in the longissimus dorsi muscle of wild pigs (WPs) and domestic pigs (DPs). Muscles sampled from postnatal day one as well as three-week-old and two-year-old animals were used in quantitative polymerase chain reaction (qPCR) assays, histological evaluations of succinate dehydrogenase (SDH) activity, and intra-myofiber lipid (IMFL) assessment. Expression of the MyHC isoforms displayed the most extensive age- and breed-dependent changes within the first three postnatal weeks. The MyHCembry level decreased significantly faster in the WPs than in the DPs. The relative MyHC-I and -IIa expression was significantly higher in the WPs, and MyHC-IIb was substantially higher in the DPs. The differences in MyHC expression corroborated the number of SDH-positive myofibers and IMFLs. Expression of the peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), peroxisome proliferator-activated receptor gamma (PPARγ) and lipoprotein lipase (LPL) genes displayed only age-related variations. In summary, the evidence is provided for accelerated postnatal myofiber transformation directed towards oxidative myofibers in WPs. The SDH activity/staining intensity largely reflected the expression of MyHCs, and not genes involved in lipid uptake and utilization.

Alterations in geometry, biomechanics, and mineral composition of juvenile rat femur induced by nonplanar PCB-155 and/or planar PCB-169.

Exposure to widespread lipophilic and bioaccumulative polychlorinated biphenyls (PCBs) induces diverse biochemical and toxicological responses in various organs, including the bone. The aim of this study was to evaluate the changes in growth rate, geometry, serum, and bone biochemical parameters and biomechanics of juvenile rat femur induced by lactational exposure to nonplanar PCB-155 and planar PCB-169 individually and in combination. Fifteen lactating Wistar rats were divided into four groups (PCB-169, PCB-155, PCB-155+169, and control), and PCBs were administered intraperitoneally at different time points after delivery. Femurs from 22-day-old offspring were analyzed by microCT, three-point bending test and inductively coupled plasma-mass spectrometry (ICP-MS) to obtain data on bone geometry, biomechanics and mineral composition. The serum levels of calcium, phosphate and alkaline phosphatase were also determined. Lactational exposure to planar PCB-169 resulted in shorter and thinner femurs, reduced endosteal and periosteal perimeters, smaller total cross-sectional and medullary areas, and lowered serum bone marker levels and calcium levels in the bone, while femur mechanical properties were not significantly altered. The changes observed in the combination exposure (PCB-155+169) group were similar to those observed in the PCB-169 group but were less pronounced. In summary, our results demonstrate that alterations in lactationally exposed offspring were primarily induced by planar PCB-169. The milder outcome in the combined group suggested that the PCB-169-mediated toxic effects on the bone might be reduced by a nonplanar PCB-155 congener. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1135-1146, 2017.

Levels and distribution of organochlorine pollutants in primary dental tissues and bone of lamb.

This study examined the bioconcentration of selected organochlorine pollutants, tetra- and hexa-chlorobiphenyls with planar (PCB-80, PCB-169) and non-planar (PCB-54, PCB-155) structure, and persistent organochlorine pesticides with planar [hexachlorobenzene (HCB)] and non-planar [1,1-bis (4-chlorophenyl)-2,2-dichloroethene (4,4'-DDE)] structure in primary dental tissues (pulp, dentine, and enamel) and mandibular bone of lactationally exposed lambs, and compared it with the organochlorines distribution pattern in permanent dental tissues and bone. Also, the role of pollutants physicochemical properties and tissue specific characteristics in the bioconcentration was assessed. Residual levels of individual pollutants were analyzed by high-resolution gas chromatography with electron-capture detection. Our results showed that transfer of organochlorines to primary hard dental tissues was higher than to permanent hard dental tissues. Metabolically more stable, planar, and toxic organochlorines (e.g. PCB-169 and HCB) predominated in primary hard dental tissues, where they may represent a potential risk for developmental dental defects.

Excretion pattern of co-planar and non-planar tetra- and hexa-chlorobiphenyls in ovine milk and faeces.

This study employed the gas chromatography with electron capture detection to determine residual levels and excretion patterns of two pairs of structurally diverse polychlorinated biphenyl (PCB) congeners (IUPAC Nos. 54, 80, 155, and 169) administered to lactating sheep by intramuscular injection. PCB levels and excretion patterns in blood, milk, and faeces were time-dependent and differed from the composition of PCB congeners administered. Lactational transfer substantially exceeded the faecal transfer. Between days 3 and 7, the amount of PCB congeners 54 and 169 excreted in milk was around 50- and 800-fold higher than the amount of these two congeners excreted via faeces. During the same period, the relative contribution of co-planar PCB congeners (80 and 169) in PCB pattern decreased in blood and increased in milk and faeces compared with non-planar PCBs (54 and 155). On day 3, the ratio PCB 169 to 54 was 7-fold higher in milk than in faeces. PCB congeners with log Kow values under 6.5 reached peaks of their excretion in milk within the first three days after administration, while the super-lipophilic PCB 169 congener with log Kow value of over 7 has not reached the plateau until day 10, but afterwards, its level remained relatively high throughout the observation period. During the 57-day follow-up period, the excretion of PCB 80, 155, and 169 in milk was 4.5-, 14-, and 46-fold greater compared with PCB 54. Differences in levels and patterns were explained with some physico-chemical properties of individual PCB congeners, such as lipophilicity, planarity, metabolic stability, sorption/diffusion properties.

The number of cells expressing dopamine D2 receptor mRNA in rat brain caudate putamen is higher in oestrus.

Dopamine D2 receptors (D2-Rs) in the central nervous system are involved in the control of locomotion, cognition, emotion and neuroendocrine secretion. The intensity of cellular responses to specific stimuli is dependent on the concentration of dopamine or its agonist, and the availability, as well as the concentration, of all the other components of the signalling pathway in the cell, including the receptors. Many factors can influence the level of mRNA encoding the receptors. In order to study the changes in the level of expression of the D2-R mRNA in the brain of female rats at different stages of the oestrous cycle, we used a quantitative in situ hybridization technique. Four groups of animals were analysed: rats in prooestrus (POE), oestrus (OE), dioestrus 1 (DOE1) and dioestrus 2 (DOE2). A 35S-labelled riboprobe was transcribed in vitro from the 1.5-kb D2-R cDNA. The caudate putamen of the rats, which shows the highest level of expression of D2-R mRNA in the brain, was examined. The number of silver grains per cell, representing hybridization of riboprobe, and the number of cells expressing the D2-R mRNA, were counted with the computer-assisted image analysis system Lucia-M. Our results show that the expression of the D2-R mRNA in the lateral striatum varies during the oestrous cycle, with the highest expression measured during DOE2. The number of cells expressing the D2-R mRNA also changes during the different phases, with the highest number being detected in OE. This indicates that during OE more cells transcribe the D2-R mRNA. The results suggest that the variations in the concentration of the D2-R mRNA in the caudate putamen of the rat brain at different stages of the reproductive cycle are caused by the combination of variable expression of the mRNA per cell and different number of the cells that express the mRNA.