scholarly journals Pharmacokinetics and central accumulation of delta-9-tetrahydrocannabinol (THC) and its bioactive metabolites are influenced by route of administration and sex in rats

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Samantha L. Baglot ◽  
Catherine Hume ◽  
Gavin N. Petrie ◽  
Robert J. Aukema ◽  
Savannah H. M. Lightfoot ◽  
...  
Keyword(s):  
Animal Studies ◽  
Data Interpretation ◽  
Bioactive Metabolites ◽  
Human Consumption ◽  
Administration Route ◽  
Sprague Dawley ◽  
North Americans ◽  
Sprague Dawley Rats ◽  
The Impact ◽  
Over Time

AbstractUp to a third of North Americans report using cannabis in the prior month, most commonly through inhalation. Animal models that reflect human consumption are critical to study the impact of cannabis on brain and behaviour. Most animal studies to date utilize injection of delta-9-tetrahydrocannabinol (THC; primary psychoactive component of cannabis). THC injections produce markedly different physiological and behavioural effects than inhalation, likely due to distinctive pharmacokinetics. The current study directly examined if administration route (injection versus inhalation) alters metabolism and central accumulation of THC and metabolites over time. Adult male and female Sprague–Dawley rats received either an intraperitoneal injection or a 15-min session of inhaled exposure to THC. Blood and brains were collected at 15, 30, 60, 90 and 240-min post-exposure for analysis of THC and metabolites. Despite achieving comparable peak blood THC concentrations in both groups, our results indicate higher initial brain THC concentration following inhalation, whereas injection resulted in dramatically higher 11-OH-THC concentration, a potent THC metabolite, in blood and brain that increased over time. Our results provide evidence of different pharmacokinetic profiles following inhalation versus injection. Accordingly, administration route should be considered during data interpretation, and translational animal work should strongly consider using inhalation models.

scholarly journals Pharmacokinetics and Central Accumulation of Delta-9-Tetrahydrocannabinol (THC) and its Bioactive Metabolites are Influenced by Route of Administration and Sex

2021 ◽  
Author(s):  
Samantha L Baglot ◽  
Catherine Hume ◽  
Gavin N. Petrie ◽  
Robert J Aukema ◽  
Savannah HM Lightfoot ◽  
...  
Keyword(s):  
Animal Studies ◽  
Data Interpretation ◽  
Bioactive Metabolites ◽  
Blood Levels ◽  
Administration Route ◽  
Sprague Dawley ◽  
North Americans ◽  
Sprague Dawley Rats ◽  
Cannabis Consumption ◽  
Over Time

Up to a third of North Americans over 16 years old report using cannabis in the prior month, most commonly through inhalation. Animal models that reflect human cannabis consumption are critical to study its impacts on brain and behaviour. Nevertheless, most animal studies to date examine effects of cannabis through injection of delta-9-tetrahydrocannabinol (THC; primary psychoactive component of cannabis). THC injections produce markedly different physiological and behavioural effects than inhalation, likely due to distinctive pharmacokinetics of each administration route. The current study directly examined if administration route (injection versus inhalation), with dosing being matched on peak THC blood levels, alters the metabolism of THC, and the central accumulation of THC and its metabolites over time. Adult male and female Sprague-Dawley rats received either a single intraperitoneal injection of THC (2.5 mg/kg) or a single (15 min) session of inhaled exposure to THC distillate (100 mg/mL) vapour. Blood and brains were collected at 15, 30, 60, 90 and 240 minutes post-exposure for analysis of THC and metabolites through mass spectrometry-liquid chromatography. Inhalation results in immediate hypothermia, whereas injection results in delayed hypothermia. Despite achieving comparable peak concentrations of blood THC in both groups, our results indicate higher initial brain THC concentration following inhalation, whereas injection resulted in dramatically higher 11-OH-THC concentrations, a potent THC metabolite, in blood and brain that increased over time. Our results provide evidence that THC and its metabolites exhibit different pharmacokinetic profiles following inhalation versus injection, which could have significant impacts for data interpretation and generalizability. Accordingly, we suggest that translational work in the realm of THC and cannabis strongly consider using inhalation models over those that employ injection.

Serotonin depletion reduces both acquisition and expression of context-conditioned fear

2021 ◽  
pp. 1-8
Author(s):  
S. Melker Hagsäter ◽  
Robert Pettersson ◽  
Axel Holmäng ◽  
Elias Eriksson
Keyword(s):  
Unconditioned Stimulus ◽  
Memory Consolidation ◽  
Clinical Studies ◽  
Conditioned Fear ◽  
Sprague Dawley ◽  
Serotonin Synthesis ◽  
Synthesis Inhibitor ◽  
Serotonin Depletion ◽  
Sprague Dawley Rats ◽  
The Impact

Abstract Objective: Whereas numerous experimental and clinical studies suggest a complex involvement of serotonin in the regulation of anxiety, it remains to be clarified if the dominating impact of this transmitter is best described as anxiety-reducing or anxiety-promoting. The aim of this study was to assess the impact of serotonin depletion on acquisition, consolidation, and expression of conditioned fear. Methods: Male Sprague–Dawley rats were exposed to foot shocks as unconditioned stimulus and assessed with respect to freezing behaviour when re-subjected to context. Serotonin depletion was achieved by administration of a serotonin synthesis inhibitor, para-chlorophenylalanine (PCPA) (300 mg/kg daily × 3), (i) throughout the period from (and including) acquisition to (and including) expression, (ii) during acquisition but not expression, (iii) after acquisition only, and (iv) during expression only. Results: The time spent freezing was significantly reduced in animals that were serotonin-depleted during the entire period from (and including) acquisition to (and including) expression, as well as in those being serotonin-depleted during either acquisition only or expression only. In contrast, PCPA administrated immediately after acquisition, that is during memory consolidation, did not impact the expression of conditioned fear. Conclusion: Intact serotonergic neurotransmission is important for both acquisition and expression of context-conditioned fear.

scholarly journals Short-Term High Fat Intake Does Not Significantly Alter Markers of Renal Function or Inflammation in Young Male Sprague-Dawley Rats

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Catherine Crinigan ◽  
Matthew Calhoun ◽  
Karen L. Sweazea
Keyword(s):  
Kidney Disease ◽  
Renal Mass ◽  
Early Stage ◽  
Young Male ◽  
Protective Effects ◽  
Sprague Dawley ◽  
High Fat ◽  
Short Term ◽  
Sprague Dawley Rats ◽  
The Impact

Chronic high fat feeding is correlated with diabetes and kidney disease. However, the impact of short-term high fat diets (HFD) is not well-understood. Six weeks of HFD result in indices of metabolic syndrome (increased adiposity, hyperglycemia, hyperinsulinemia, hyperlipidemia, hyperleptinemia, and impaired endothelium-dependent vasodilation) compared to rats fed on standard chow. The hypothesis was that short-term HFD would induce early signs of renal disease. Young male Sprague-Dawley rats were fed either HFD (60% fat) or standard chow (5% fat) for six weeks. Morphology was determined by measuring changes in renal mass and microstructure. Kidney function was measured by analyzing urinary protein, creatinine, and hydrogen peroxide (H2O2) concentrations, as well as plasma cystatin C concentrations. Renal damage was measured through assessment of urinary oxDNA/RNA concentrations as well as renal lipid peroxidation, tumor necrosis factor alpha (TNFα), and interleukin 6 (IL-6). Despite HFD significantly increasing adiposity and renal mass, there was no evidence of early stage kidney disease as measured by changes in urinary and plasma biomarkers as well as histology. These findings suggest that moderate hyperglycemia and inflammation produced by short-term HFD are not sufficient to damage kidneys or that the ketogenic HFD may have protective effects within the kidneys.

scholarly journals Structural Alteration in Dermal Vessels and Collagen Bundles following Exposure of Skin Wound to Zeolite–Bentonite Compound

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Shahram Paydar ◽  
Ali Noorafshan ◽  
Behnam Dalfardi ◽  
Shahram Jahanabadi ◽  
Seyed Mohammad Javad Mortazavi ◽  
...  
Keyword(s):  
Healing Process ◽  
Volume Density ◽  
Skin Wound ◽  
Sprague Dawley ◽  
Small Vessels ◽  
Sprague Dawley Rats ◽  
Significant Difference ◽  
Sterile Normal Saline ◽  
Animal Skin ◽  
The Impact

Background. This study examines the impact of one-time direct application of haemostatic agent zeolite–bentonite powder to wounded skin on the healing process in rats. Materials and Methods. 24 male Sprague-Dawley rats were randomly allocated into two groups (n=12): (1) the rats whose wounds were washed only with sterile normal saline (NS-treated) and (2) those treated with zeolite–bentonite compound (ZEO-treated). The wound was circular, full-thickness, and 2 cm in diameter. At the end of the 12th day, six animals from each group were randomly selected and terminated. The remaining rats were terminated after 21 days. Just after scarification, skin samples were excised and sent for stereological evaluation. Results. The results showed a significant difference between the two groups regarding the length density of the blood vessels and diameter of the large and small vessels on the 12th day after the wound was inflicted. Besides, volume density of both the dermis and collagen bundles was reduced by 25% in the ZEO-treated rats in comparison to the NS-treated animals after 21 days. Conclusions. One-time topical usage of zeolite–bentonite haemostatic powder on an animal skin wound might negatively affect the healing process through vasoconstriction and inhibition of neoangiogenesis.

scholarly journals Norepinephrine-evoked salt-sensitive hypertension requires impaired renal sodium chloride cotransporter activity in Sprague-Dawley rats

2016 ◽  
Vol 310 (2) ◽  
pp. R115-R124 ◽  
Author(s):  
Kathryn R. Walsh ◽  
Jill T. Kuwabara ◽  
Joon W. Shim ◽  
Richard D. Wainford
Keyword(s):  
Blood Pressure ◽  
Sodium Chloride ◽  
Salt Sensitivity ◽  
Dietary Sodium ◽  
Ang Ii ◽  
Sprague Dawley ◽  
Sodium Chloride Cotransporter ◽  
Sprague Dawley Rats ◽  
Salt Sensitive Hypertension ◽  
The Impact

Recent studies have implicated a role of norepinephrine (NE) in the activation of the sodium chloride cotransporter (NCC) to drive the development of salt-sensitive hypertension. However, the interaction between NE and increased salt intake on blood pressure remains to be fully elucidated. This study examined the impact of a continuous NE infusion on sodium homeostasis and blood pressure in conscious Sprague-Dawley rats challenged with a normal (NS; 0.6% NaCl) or high-salt (HS; 8% NaCl) diet for 14 days. Naïve and saline-infused Sprague-Dawley rats remained normotensive when placed on HS and exhibited dietary sodium-evoked suppression of peak natriuresis to hydrochlorothiazide. NE infusion resulted in the development of hypertension, which was exacerbated by HS, demonstrating the development of the salt sensitivity of blood pressure [MAP (mmHg) NE+NS: 151 ± 3 vs. NE+HS: 172 ± 4; P < 0.05]. In these salt-sensitive animals, increased NE prevented dietary sodium-evoked suppression of peak natriuresis to hydrochlorothiazide, suggesting impaired NCC activity contributes to the development of salt sensitivity [peak natriuresis to hydrochlorothiazide (μeq/min) Naïve+NS: 9.4 ± 0.2 vs. Naïve+HS: 7 ± 0.1; P < 0.05; NE+NS: 11.1 ± 1.1; NE+HS: 10.8 ± 0.4). NE infusion did not alter NCC expression in animals maintained on NS; however, dietary sodium-evoked suppression of NCC expression was prevented in animals challenged with NE. Chronic NCC antagonism abolished the salt-sensitive component of NE-mediated hypertension, while chronic ANG II type 1 receptor antagonism significantly attenuated NE-evoked hypertension without restoring NCC function. These data demonstrate that increased levels of NE prevent dietary sodium-evoked suppression of the NCC, via an ANG II-independent mechanism, to stimulate the development of salt-sensitive hypertension.

scholarly journals The Impact of DJOS Surgery, a High Fat Diet and a Control Diet on the Enzymes of Glucose Metabolism in the Liver and Muscles of Sprague-Dawley Rats

2019 ◽  
Vol 10 ◽  
Author(s):  
Dominika Stygar ◽  
Dorian Andrare ◽  
Barbara Bażanów ◽  
Elżbieta Chełmecka ◽  
Tomasz Sawczyn ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
High Fat Diet ◽  
Control Diet ◽  
Sprague Dawley ◽  
High Fat ◽  
Sprague Dawley Rats ◽  
The Impact

scholarly journals Effects of Diet-Induced Obesity and Deficient in Vitamin D on Spermatozoa Function and DNA Integrity in Sprague-Dawley Rats

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
O. Merino ◽  
R. Sánchez ◽  
B. M. Gregorio ◽  
F. J. Sampaio ◽  
J. Risopatrón
Keyword(s):  
Vitamin D ◽  
Dna Fragmentation ◽  
High Fat Diet ◽  
Control Diet ◽  
Sperm Function ◽  
Sprague Dawley ◽  
High Fat ◽  
Diet Induced Obesity ◽  
Sprague Dawley Rats ◽  
The Impact

Obesity has adverse effects on male fertility and usually is diagnosed with a prevalence of vitamin D deficiency (VD-). Discussion on the impact of obesity/VD- on sperm function has been limited. This study analyzed the effects of diet-induced obesity/VD- on viability and plasma membrane integrity (PMI), superoxide anion (O2-) level, and DNA fragmentation (DNAfrag) in sperm Sprague-Dawley rats. The males were randomized into four groups and fed for a period of 12 weeks: G1: control diet with vitamin D (C/VD+), G2: control diet without vitamin D (C/VD-), G3: high-fat diet with vitamin D (HF/VD+), and G4: high-fat diet without vitamin D (HF/VD-). Sperm function parameters were analyzed by flow cytometry. PMI percentages and O2- levels were not affected by any of the diets. DNA fragmentation was increasing significantly (p<0.05) in the spermatozoa of animals with diets vitamin D deficient (G2) and diet-induced obesity (G4). Our results allow us to point out that diet-induced obesity and VD- produce greater damage in DNA sperm of rats. The use of nutraceuticals containing vitamin D could be reducing the risk of fragmentation of DNA in spermatozoa.

scholarly journals Pulmonary Toxicity, Distribution, and Clearance of Intratracheally Instilled Silicon Nanowires in Rats

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Jenny R. Roberts ◽  
Robert R. Mercer ◽  
Rebecca S. Chapman ◽  
Guy M. Cohen ◽  
Sarunya Bangsaruntip ◽  
...  
Keyword(s):  
Silicon Nanowires ◽  
Pulmonary Toxicity ◽  
Lung Damage ◽  
Collagen Deposition ◽  
Wire Length ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Dose Dependent ◽  
Over Time

Silicon nanowires (Si NWs) are being manufactured for use as sensors and transistors for circuit applications. The goal was to assess pulmonary toxicity and fate of Si NW using anin vivoexperimental model. Male Sprague-Dawley rats were intratracheally instilled with 10, 25, 50, 100, or 250 μg of Si NW (~20–30 nm diameter; ~2–15 μm length). Lung damage and the pulmonary distribution and clearance of Si NW were assessed at 1, 3, 7, 28, and 91 days after-treatment. Si NW treatment resulted in dose-dependent increases in lung injury and inflammation that resolved over time. At day 91 after treatment with the highest doses, lung collagen was increased. Approximately 70% of deposited Si NW was cleared by 28 days with most of the Si NW localized exclusively in macrophages. In conclusion, Si NW induced transient lung toxicity which may be associated with an early rapid particle clearance; however, persistence of Si NW over time related to dose or wire length may lead to increased collagen deposition in the lung.

scholarly journals Hyperosmolarity in the small intestine contributes to postprandial ghrelin suppression

2014 ◽  
Vol 306 (12) ◽  
pp. G1108-G1116 ◽  
Author(s):  
Joost Overduin ◽  
Tracy S. Tylee ◽  
R. Scott Frayo ◽  
David E. Cummings
Keyword(s):  
Small Intestine ◽  
Glucose Solution ◽  
Jugular Vein ◽  
Gastric Bypass Surgery ◽  
Sprague Dawley ◽  
Macronutrient Composition ◽  
Sprague Dawley Rats ◽  
Small Intestinal ◽  
The Impact ◽  
Dietary Modifications

Plasma levels of the orexigenic hormone ghrelin are suppressed by meals with an efficacy dependent on their macronutrient composition. We hypothesized that heterogeneity in osmolarity among macronutrient classes contributes to these differences. In three studies, the impact of small intestinal hyperosmolarity was examined in Sprague-Dawley rats. In study 1, isotonic, 2.5×, and 5× hypertonic solutions of several agents with diverse absorption and metabolism properties were infused duodenally at a physiological rate (3 ml/10 min). Jugular vein blood was sampled before and at 30, 60, 90, 120, 180, 240, and 300 min after infusion. Plasma ghrelin was suppressed dose dependently and most strongly by glucose. Hyperosmolar infusions of lactulose, which transits the small intestine unabsorbed, and 3- O-methylglucose (3- O-MG), which is absorbed like glucose but remains unmetabolized, also suppressed ghrelin. Glucose, but not lactulose or 3- O-MG, infusions increased plasma insulin. In study 2, intestinal infusions of hyperosmolar NaCl suppressed ghrelin, a response that was not attenuated by coinfusion with the neural blocker lidocaine. In study 3, we reconfirmed that the low-osmolar lipid emulsion Intralipid suppresses ghrelin more weakly than isocaloric (but hypertonic) glucose. Importantly, raising Intralipid's osmolarity to that of the glucose solution by nonabsorbable lactulose supplementation enhanced ghrelin suppression to that seen after glucose. Hyperosmolar ghrelin occurred particularly during the initial 3 postinfusion hours. We conclude that small intestinal hyperosmolarity 1) is sufficient to suppress ghrelin, 2) may combine with other postprandial mechanisms to suppress ghrelin, 3) might contribute to altered ghrelin regulation after gastric bypass surgery, and 4) may inform dietary modifications for metabolic health.

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