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Fogarty MJ, Rana S, Mantilla CB, Sieck GC. Quantifying mitochondrial volume density in phrenic motor neurons. J Neurosci Methods 2021; 353:109093. [PMID: 33549636 PMCID: PMC7990712 DOI: 10.1016/j.jneumeth.2021.109093] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 12/31/2022]
Abstract
BACKGROUND Previous assessments of mitochondrial volume density within motor neurons used electron microscopy (EM) to image mitochondria. However, adequate identification and sampling of motor neurons within a particular motor neuron pool is largely precluded using EM. Here, we present an alternative method for determining mitochondrial volume density in identified motor neurons within the phrenic motor neuron (PhMN) pool, with greatly increased sampling. NEW METHOD This novel method for assessing mitochondrial volume density in PhMNs uses a combination of intrapleural injection of Alexa 488-conjugated cholera toxin B (CTB) to retrogradely label PhMNs, followed by intrathecal application of MitoTracker Red to label mitochondria. This technique was validated by comparison to 3D EM determination of mitochondrial volume density as a "gold standard". RESULTS A mean mitochondrial volume density of ∼11 % was observed across PhMNs using the new MitoTracker Red method. This compared favourably with mitochondrial volume density (∼11 %) measurements using EM. COMPARISON WITH EXISTING METHOD The range, mean and variance of mitochondrial volume density estimates in PhMNs were not different between EM and fluorescent imaging techniques. CONCLUSIONS Fluorescent imaging may be used to estimate mitochondrial volume density in a large sample of motor neurons, with results similar to EM, although EM did distinguish finer mitochondrion morphology compared to MitoTracker fluorescence. Compared to EM methods, the assessment of a larger sample size and unambiguous identification of motor neurons belonging to a specific motor neuron pool represent major advantages over previous methods.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, United States; School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, 4067, Australia
| | - Sabhya Rana
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, United States
| | - Carlos B Mantilla
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, United States; Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, 55905, United States
| | - Gary C Sieck
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, United States.
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Lilius TO, Jokinen V, Neuvonen MS, Niemi M, Kalso EA, Rauhala PV. Ketamine coadministration attenuates morphine tolerance and leads to increased brain concentrations of both drugs in the rat. Br J Pharmacol 2016; 172:2799-813. [PMID: 25297798 PMCID: PMC4439876 DOI: 10.1111/bph.12974] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 09/05/2014] [Accepted: 10/03/2014] [Indexed: 12/25/2022] Open
Abstract
Background and Purpose The effects of ketamine in attenuating morphine tolerance have been suggested to result from a pharmacodynamic interaction. We studied whether ketamine might increase brain morphine concentrations in acute coadministration, in morphine tolerance and morphine withdrawal. Experimental Approach Morphine minipumps (6 mg·day–1) induced tolerance during 5 days in Sprague–Dawley rats, after which s.c. ketamine (10 mg·kg–1) was administered. Tail flick, hot plate and rotarod tests were used for behavioural testing. Serum levels and whole tissue brain and liver concentrations of morphine, morphine-3-glucuronide, ketamine and norketamine were measured using HPLC-tandem mass spectrometry. Key Results In morphine-naïve rats, ketamine caused no antinociception whereas in morphine-tolerant rats there was significant antinociception (57% maximum possible effect in the tail flick test 90 min after administration) lasting up to 150 min. In the brain of morphine-tolerant ketamine-treated rats, the morphine, ketamine and norketamine concentrations were 2.1-, 1.4- and 3.4-fold, respectively, compared with the rats treated with morphine or ketamine only. In the liver of morphine-tolerant ketamine-treated rats, ketamine concentration was sixfold compared with morphine-naïve rats. After a 2 day morphine withdrawal period, smaller but parallel concentration changes were observed. In acute coadministration, ketamine increased the brain morphine concentration by 20%, but no increase in ketamine concentrations or increased antinociception was observed. Conclusions and Implications The ability of ketamine to induce antinociception in rats made tolerant to morphine may also be due to increased brain concentrations of morphine, ketamine and norketamine. The relevance of these findings needs to be assessed in humans.
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Affiliation(s)
- T O Lilius
- Institute of Biomedicine, Pharmacology, University of Helsinki, Finland
| | - V Jokinen
- Institute of Biomedicine, Pharmacology, University of Helsinki, Finland
| | - M S Neuvonen
- Haartman Institute, Department of Clinical Pharmacology, University of Helsinki, Finland
| | - M Niemi
- Haartman Institute, Department of Clinical Pharmacology, University of Helsinki, Finland.,HUSLAB, Helsinki University Central Hospital, Finland
| | - E A Kalso
- Institute of Biomedicine, Pharmacology, University of Helsinki, Finland.,Department of Anaesthesia, Intensive Care Medicine, Emergency Medicine and Pain Medicine, Pain Clinic, Helsinki University Central Hospital, Finland
| | - P V Rauhala
- Institute of Biomedicine, Pharmacology, University of Helsinki, Finland
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Giroux MC, Santamaria R, Hélie P, Burns P, Beaudry F, Vachon P. Physiological, pharmacokinetic and liver metabolism comparisons between 3-, 6-, 12- and 18-month-old male Sprague Dawley rats under ketamine-xylazine anesthesia. Exp Anim 2015; 65:63-75. [PMID: 26489361 PMCID: PMC4783652 DOI: 10.1538/expanim.15-0039] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The main objective of this study was to compare the physiological changes (withdrawal and
corneal reflexes, respiratory and cardiac frequency, blood oxygen saturation, and rectal
temperature) following intraperitoneal administration of ketamine (80 mg/kg) and xylazine
(10 mg/kg) to 3-, 6-, 12- and 18-month-old male Sprague Dawley rats (n=6/age group).
Plasma pharmacokinetics, liver metabolism, and blood biochemistry were examined for a
limited number of animals to better explain anesthetic drug effects. Selected organs were
collected for histopathology. The results for the withdrawal and corneal reflexes suggest
a shorter duration and decreased depth of anesthesia with aging. Significant cardiac and
respiratory depression, as well as decreased blood oxygen saturation, occurred in all age
groups however, cardiac frequency was the most affected parameter with aging, since the
6-, 12-, and 18-month-old animals did not recuperate to normal values during recovery from
anesthesia. Pharmacokinetic parameters (T1/2 and AUC) increased and drug
clearance decreased with aging, which strongly suggests that drug exposure is associated
with the physiological results. The findings for liver S9 fractions of 18-month-old rats
compared with the other age groups suggest that following a normal ketamine anesthetic
dose (80 mg/kg), drug metabolism is impaired, leading to a significant increase of drug
exposure. In conclusion, age and related factors have a substantial effect on ketamine and
xylazine availability, which is reflected by significant changes in pharmacokinetics and
liver metabolism of these drugs, and this translates into shorter and less effective
anesthesia with increasing age.
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Affiliation(s)
- Marie-Chantal Giroux
- Department of Veterinary Biomedicine, University of Montreal, Saint-Hyacinthe, Quebec, Canada
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Assessing the Impact of Capture on Wild Animals: The Case Study of Chemical Immobilisation on Alpine Ibex. PLoS One 2015; 10:e0130957. [PMID: 26111118 PMCID: PMC4482404 DOI: 10.1371/journal.pone.0130957] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/27/2015] [Indexed: 11/19/2022] Open
Abstract
The importance of capturing wild animals for research and conservation projects is widely shared. As this activity continues to become more common, the need to assess its negative effects increases so as to ensure ethical standards and the validity of research results. Increasing evidence has revealed that indirect (physiological and behavioural) effects of capture are as important as direct risks (death or injury) and that different capture methodologies can cause heterogeneous effects. We investigated the influence of chemical immobilisation on Alpine ibex (Capra ibex): during the days following the capture we collected data on spatial behaviour, activity levels of both males and females, and male hormone levels. Moreover, we recorded the reproductive status of each marked female during the breeding seasons of 15 years. Then, by several a priori models we investigated the effects of the capture taking into account biological factors and changes in environmental conditions. Our results showed that chemical immobilisation did not affect either spatial behaviour (for both males and females) or male hormone levels, though both sexes showed reduced activity levels up to two days after the capture. The capture did not significantly affect the likelihood for a female to give birth in the following summer. Our findings highlighted the scarce impact of chemical immobilisation on ibex biology, as we detected alteration of activity levels only immediately after the capture if compared to the following days (i.e., baseline situation). Hence, the comparison of our findings with previous research showed that our methodology is one of the less invasive procedures to capture large mammals. Nonetheless, in areas characterised by high predator density, we suggest that animals released be carefully monitored for some hours after the capture. Moreover, researchers should avoid considering data collected during the first days after the manipulation in order to avoid biased information.
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Giroux MC, Hélie P, Burns P, Vachon P. Anesthetic and pathological changes following high doses of ketamine and xylazine in Sprague Dawley rats. Exp Anim 2015; 64:253-60. [PMID: 25818316 PMCID: PMC4547998 DOI: 10.1538/expanim.14-0088] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The main objective of this study was to compare the effects of ketamine and xylazine in aging rats when coadministered intraperitoneally at high anesthetic doses. Three groups (n=6 rats/group) consisting of rats at 3, 6 and 12 months of age were used. During anesthesia, animals were monitored for heart rate, respiratory frequency, blood oxygen saturation, and rectal temperature. The corneal and paw withdrawal reflex were also examined during anesthesia. During anesthesia, withdrawal and corneal reflexes were absent for progressively longer durations with increasing age. Significant decreases in cardiac and respiratory frequency and, blood oxygen saturation occurred for the 6- and 12-month-old animals. Respiratory frequency and blood oxygen saturation returned to normal at the end of the anesthesia; however, the significant decrease in cardiac frequency persisted in the 6- and 12-month-old animals. Rectal temperature was decreased significantly only in the 3-month-old animals. Pulmonary edema and effusion occurred in 50% of the 12-month-old animals. In conclusion, if ketamine-xylazine are used for anesthesia, the doses should be optimized for the age of the subjects prior to initiation of the research project.
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Affiliation(s)
- Marie-Chantal Giroux
- Faculty of Veterinary Medicine, Departments of Veterinary Biomedicine, University of Montreal, 3200 rue Sicotte, Saint-Hyacinthe, Quebec, J2S 2M2, Canada
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Jaber SM, Hankenson FC, Heng K, McKinstry-Wu A, Kelz MB, Marx JO. Dose regimens, variability, and complications associated with using repeat-bolus dosing to extend a surgical plane of anesthesia in laboratory mice. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2014; 53:684-691. [PMID: 25650976 PMCID: PMC4253583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 03/25/2014] [Accepted: 05/01/2014] [Indexed: 06/04/2023]
Abstract
Extending a surgical plane of anesthesia in mice by using injectable anesthetics typically is accomplished by repeat-bolus dosing. We compared the safety and efficacy of redosing protocols administered either during an anesthetic surgical plane (maintaining a continuous surgical plane, CSP), or immediately after leaving this plane (interrupted surgical plane, ISP) in C57BL/6J mice. Anesthesia was induced with ketamine, xylazine, and acepromazine (80, 8, and 1 mg/kg IP, respectively), and redosing protocols included 25% (0.25K), 50% (0.5K), or 100% (1.0K) of the initial ketamine dose or 25% (0.25KX) or 50% (0.5KX) of the initial ketamine-xylazine dose. In the ISP group, the surgical plane was extended by 13.8 ± 2.1 min (mean ± SEM) after redosing for the 0.25K redose with 50% returning to a surgical plane, 42.7 ± 4.5 min for the 0.5K redose with 88% returning to a surgical plane, and 44.3 ± 15.4 min for the 1.0K redose, 52.8 ± 7.2 min for the 0.25KX redose, and 45.9 ± 2.9 min for the 0.5KX redose, with 100% of mice returning to a surgical plane of anesthesia in these 3 groups. Mortality rates for ISP groups were 0%, 12%, 33%, 12%, and 18%, respectively. Mice in CSP groups had 50% mortality, independent of the repeat-dosing protocol. We recommend redosing mice with either 50% of the initial ketamine dose or 25% of the initial ketamine-xylazine dose immediately upon return of the pedal withdrawal reflex to extend the surgical plane of anesthesia in mice, optimize the extension of the surgical plane, and minimize mortality.
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Affiliation(s)
- Samer M Jaber
- University Laboratory Animal Resources, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - F Claire Hankenson
- University Laboratory Animal Resources, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kathleen Heng
- School of Veterinary Medicine, University of California, Davis, California, USA
| | - Andrew McKinstry-Wu
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Max B Kelz
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - James O Marx
- University Laboratory Animal Resources, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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Nieto A, Hou H, Sailor MJ, Freeman WR, Cheng L. Ocular silicon distribution and clearance following intravitreal injection of porous silicon microparticles. Exp Eye Res 2013; 116:161-8. [PMID: 24036388 DOI: 10.1016/j.exer.2013.09.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/27/2013] [Accepted: 09/02/2013] [Indexed: 11/25/2022]
Abstract
Porous silicon (pSi) microparticles have been investigated for intravitreal drug delivery and demonstrated good biocompatibility. With the appropriate surface chemistry, pSi can reside in vitreous for months or longer. However, ocular distribution and clearance pathway of its degradation product, silicic acid, are not well understood. In the current study, rabbit ocular tissue was collected at different time point following fresh pSi (day 1, 5, 9, 16, and 21) or oxidized pSi (day 3, 7, 14, 21, and 35) intravitreal injection. In addition, dual-probe simultaneous microdialysis of aqueous and vitreous humor was performed following a bolus intravitreal injection of 0.25 mL silicic acid (150 μg/mL) and six consecutive microdialysates were collected every 20 min. Silicon was quantified from the samples using inductively coupled plasma-optical emission spectroscopy. The study showed that following the intravitreal injection of oxidized pSi, free silicon was consistently higher in the aqueous than in the retina (8.1 ± 6.5 vs. 3.4 ± 3.9 μg/mL, p = 0.0031). The area under the concentration-time curve (AUC) of the retina was only about 24% that of the aqueous. The mean residence time was 16 days for aqueous, 13 days for vitreous, 6 days for retina, and 18 days for plasma. Similarly, following intravitreal fresh pSi, free silicon was also found higher in aqueous than in retina (7 ± 4.7 vs. 3.4 ± 4.1 μg/mL, p = 0.014). The AUC for the retina was about 50% of the AUC for the aqueous. The microdialysis revealed the terminal half-life of free silicon in the aqueous was 30 min and 92 min in the vitreous; the AUC for aqueous accounted for 38% of the AUC for vitreous. Our studies indicate that aqueous humor is a significant pathway for silicon egress from the eye following intravitreal injection of pSi crystals.
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Affiliation(s)
- Alejandra Nieto
- Jacobs Retina Center at Shiley Eye Center at University of California, San Diego, USA; Department of Chemistry and Biochemistry, University of California, San Diego, USA
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Veilleux-Lemieux D, Castel A, Carrier D, Beaudry F, Vachon P. Pharmacokinetics of ketamine and xylazine in young and old Sprague-Dawley rats. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2013; 52:567-570. [PMID: 24041212 PMCID: PMC3784662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 01/28/2013] [Accepted: 03/12/2013] [Indexed: 06/02/2023]
Abstract
To compare the pharmacokinetics of coadministered intraperitoneal ketamine and xylazine in young (8 to 10 wk; n = 6) and old rats (2 to 2.4 y; n = 6), blood samples obtained at 15 and 30 min and 1, 2, and 4 h after drug administration were analyzed by HPLC-tandem mass spectrometry. In both groups, the withdrawal reflex was absent during anesthesia and was present at 1.1 (± 0.2) and 2.6 (± 0.7) h after drug administration in young and old rats, respectively, with the first voluntary movement at 1.5 ± 0.2 and 4.9 ± 1.0 h. Drug availability of ketamine and xylazine was 6.0 and 6.7 times greater, respectively, in old than young rats. The rate constant of elimination of both drugs was greatly decreased and the elimination half-life was significantly greater in old compared with young rats. In conclusion, age and associated factors affect the availability of ketamine and xylazine when coadministered to attain clinical anesthesia, changing the pharmacokinetics of these drugs and prolonging anesthesia duration and recovery times with aging. Compared with their young counterparts, aged rats required much higher doses to attain a similar level of anesthesia. Finally, the long half-life of both ketamine and xylazine, when coadministered to old rats, may be a factor in research protocols because residual plasma concentrations could still be present for as long as 3 and 5 d, respectively, after administration.
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Affiliation(s)
| | - Aude Castel
- Faculty of Veterinary Medicine, Department of Veterinary Biomedicine, Saint-Hyacinthe, Quebec, Canada
| | | | - Francis Beaudry
- Faculty of Veterinary Medicine, Department of Veterinary Biomedicine, Saint-Hyacinthe, Quebec, Canada
| | - Pascal Vachon
- Faculty of Veterinary Medicine, Department of Veterinary Biomedicine, Saint-Hyacinthe, Quebec, Canada
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