Specific Diseases and Procedures
Michele Barletta, Jane Quandt, Rachel Reed in Equine Anesthesia and Pain Management, 2023
Drugs. Combine with cardiac massage epinephrine 0.01 mg/kg IV.Doxapram is a respiratory stimulant and also will partially antagonize sedation from xylazine or detomidine passed through the placenta from the mare. Inject 0.5 mg/kg, approximately 1.25 ml for a large foal, intravenously.Antagonism of drugs administered to the mare that may have crossed to the foal. Naloxone is an opioid antagonist. Inject 0.01 mg/kg, approximately 1.0 ml (0.4 mg/ml, for a large foal). Atipamezole will antagonize an alpha-2 agonist sedative.Dopamine and dobutamine are cardiovascular stimulants. Dopamine is more effective for resuscitation because it increases heart rate in addition to myocardial contractility. Add 50 mg dopamine (1.25 ml of 40 mg/ml) to 500 ml saline to make a solution of 100 µg/ml. Infuse IV at 7–10 µg/kg/min; for a 50 kg/110 lb foal, 8 µg/kg/min using a 15 drops/ml administration set is one drop/second.Tactile stimulation by rubbing with a towel; tickle inside the nostrils and ears and the perineum.
Neuroimaging Applications for the Study of Alzheimer’s Disease
Zaven S. Khachaturian, Teresa S. Radebaugh in Alzheimer’s Disease, 2019
In view of the morphological and chemical evidence of presynaptic loss in AD, it is reasonable to pursue in vivo measures of presynaptic function in order to map the degeneration in AD. The development of such markers would have important consequences for understanding the pathophysiology of AD, improving its diagnosis, and monitoring the effects of treatment. Selective markers offer the ability to relate changes in specific neurochemical systems to the biological heterogeneity of the disease. Specific ligands which are in development for the presynaptic systems of interest are L-dopa and m-tyrosine for the dopaminergic system, nitroquipazine for the serotonergic system,56 and derivatives of vesamicol for the cholinergic system.57 The latter two have been labeled for SPECT studies but have the potential for high-resolution PET studies. Even at poorer resolution, these two ligands have promise in investigations of the regional changes in serotonergic and cholinergic system. The α-adrenergic system represented in thin cortical layers and small nuclei of the periaqueductal gray is also a target for PET studies. In this case the available ligand is atipamezole an α2 postsynaptic antagonist.58
Reviving matrix for nerve reconstruction in rat model of acute and chronic complete spinal cord injury
Published in Neurological Research, 2022
Shimon Rochkind, Mara Almog, Zvi Nevo
Noninvasive electrophysiology evaluation was performed before the surgical procedure and again at the end of study. The recordings were performed from both hindlimbs using a Dantec® KEYPONT® Focus device (Natus Medical Inc., USA). The measurements were conducted on anesthetized rats using an intraperitoneal injection of ketamine (60 mg/kg; Vetmarket, Israel) and medetomidine (0.25 mg/kg; Vetmarket, Israel) mixture. Bipolar stimulating needle electrodes were placed at the gastrocnemius muscle (cathode) and another one subcutaneously at the foot pad level (anode). The somatosensory evoked potentials (SEPs) were recorded through bipolar needle electrodes, when one needle electrode placed subcutaneously between the eyes (anode) and the other over the approximate location of the somatosensory cortex (cranial level) and served as a cathode. For ground, an electrode was placed subcutaneously in the lumbar region. Throughout the evaluation an average of 300 single pulses was delivered having a duration of 0.2 ms at a rate of 3/sec. The stimulus intensity was increased gradually, until appearance of twitching of the hindlimb. Then, somatosensory evoked potentials (SEPs) were recorded. At the end of the measurement the rats received an intraperitoneally dose of atipamezole hydrochloride (Vetmarket, Israel), as an antidote (1 mg/kg). The appearance of a SEP signal in two consecutive tests was considered positive.
Recent developments in predicting CYP-independent metabolism
Published in Drug Metabolism Reviews, 2021
Nikhilesh V. Dhuria, Bianka Haro, Amit Kapadia, Khadjia A. Lobo, Bernice Matusow, Mary A. Schleiff, Christina Tantoy, Jasleen K. Sodhi
Atipamezole was demonstrated to more potently inhibit the major CYP isoforms than ABT with IC50 values less than 10 µM in all evaluations (with and without preincubation, in human, rat, and dog liver microsomes, and for all CYP isoforms) (Li et al. 2019c). The inhibitory potential of atipamezole was similar both with and without preincubation, indicating that atipamezole is a reversible CYP inhibitor and thus does not require preincubation in in vitro phenotyping assays. In contrast, the inhibitory potential of ABT varied greatly for each isoform with IC50 values with preincubation ranging from 2.7 to 460 µM in human liver microsomes, thus confirming results from previous studies (Emoto et al. 2003; Linder et al. 2009). Similar results were obtained for dog and rat liver microsomes. With respect to CYP2C9-mediated diclofenac metabolism, atipamezole potently inhibited the reaction with IC50 values of 1.8 µM and 1.5 µM with and without preincubation, respectively, whereas ABT resulted in less potent inhibition with IC50 values of 460 µM and 1083 µM, respectively. Next, it was confirmed in vivo in rats that both agents had the potential to inhibit diclofenac metabolism. Of note, it was also demonstrated that atipamezole does not inhibit P-glycloprotein (P-gp) in vitro and results were confirmed with rat pharmacokinetic studies using the P-gp substrate fexofenadine. In comparison, it has been previously reported that ABT also does not have inhibitory effects on P-gp nor on other clinically relevant xenobiotic transporters (Cheong et al. 2017).
Blast Exposure Induces Ocular Functional Changes with Increasing Blast Over-pressures in a Rat Model
Published in Current Eye Research, 2019
Yanli Zhu, Jeffrey T. Howard, Peter R. Edsall, Ryan B. Morris, Brian J. Lund, Jeffery M. Cleland
Adult male Long-Evans rats weighing 250–400 g (Envigo RMS, Inc., USA) were used for this study. The animals were housed with free access to food and water in a 12-h dark-light cycle at 22°C. A total of 28 adult male Long-Evans rats were randomly assigned to one of the four blast-wave exposure groups or one unexposed control (sham-blast) group (n = 5–7/group). Ocular functional changes in response to blast doses were evaluated in acute and chronic stages for up to eight weeks after blast-wave exposure. Assessments included clinical eye examination, intraocular pressure (IOP) measurements, flash electroretinography (fERG) recordings, and retinal spectral-domain optical coherence tomography (SD-OCT) imaging. Assessments were conducted according to the schedule listed in Table 1. For all procedures, rats were anesthetized with a mixture of Ketamine and Dexmedetomidine (Ketamine 50 mg/kg/Dexmedetomidine 0.25 mg/kg; Zoetis Inc., Kalamazoo MI) administered via intraperitoneal injection. Once procedures were completed, a dexmedetomidine antidote of Atipamezole Hydrochloride (1.0 mg/kg; Pfizer Animal Health, NY, NY) was administered by subcutaneous injection resulting in rapid reversal of anesthetic effect and recovery from the anesthesia. To minimize potential pain and/or distress, all rats (including shame controls) undergoing the blast exposure received a preemptive analgesic dose of sustained release Buprenorphine SR LAB (1.2 mg/kg; ZooPharm, Fort Collins, CO) delivered by subcutaneous injection 15 min prior to the blast exposure. Following each assessment, bacitracin ophthalmic ointment was applied prophylactically to both eyes.
Related Knowledge Centers
- Adrenergic Antagonist
- Dexmedetomidine
- Intramuscular Injection
- Racemic Mixture
- Xylazine
- Adrenergic Receptor
- Alpha-2 Adrenergic Receptor
- Medetomidine
- Intravenous Therapy
- Analgesic