Effects of anesthetics on systemic hemodynamics in mice

Janssen, Ben J. A.; Celle, Tijl De; Debets, Jacques; Brouns, A.; Callahan, Michael F.; Smith, Thomas L.

doi:10.1152/ajpheart.01192.2003

Cited by 274 publications

(248 citation statements)

References 30 publications

(41 reference statements)

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“…Oscillatory activity under urethane anesthesia in mice Urethane, a carcinogenic substance, is favored for acute in vivo electrophysiological experiments because it induces long-lasting steady level of anesthesia with muscle relaxation (Maggi and Meli, 1986a) and minimally affects the autonomic and cardiovascular systems (Maggi and Meli, 1986b;Hara and Harris, 2002;Janssen et al, 2004). Most of our knowledge about the specific neurons involved in various brain oscillations comes from urethane anesthetized rats (Klausberger and Somogyi, 2008).…”

Section: Discussionmentioning

confidence: 99%

Changes in Hippocampal Neuronal Activity During and After Unilateral Selective Hippocampal IschemiaIn Vivo

Barth¹,

Módy²

2011

J. Neurosci.

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The hippocampal formation is one of the brain regions most sensitive to ischemic damage. However, there are no studies about changes in hippocampal neuronal activity during and after a selective unilateral hippocampal ischemia. We developed a novel unilateral cerebrovascular ischemia model in mice that selectively shuts down blood supply to the ipsilateral hippocampal formation. Using a modified version of the photothrombotic method, we stereotaxically targeted the initial ascending part of the longitudinal hippocampal artery in urethane anesthetized and rose bengal-injected mice. To block blood flow in the targeted artery, we photoactivated the rose bengal by illuminating the longitudinal hippocampal artery through an optical fiber inserted into the brain. In vivo field potential recordings in the CA1 region of the hippocampus before, during and after the induction of ischemia demonstrated a high-frequency discharge (HFD) reaching frequencies of Ͼ300 Hz and lasting 7-24 s during the illumination consistent with a massive synchronous neuronal activity. The HFD was invariably followed by a DC voltage shift and a decreased activity at both low (30 -57 Hz)-and high (63-119 Hz)-gamma frequencies. This decrease in gamma activity lasted for the entire duration of the recordings (ϳ160 min) following ischemia. The contralateral hippocampus displayed HFDs but with different frequency spectra and without DC voltage shifts or long-lasting decreases in gamma oscillations. Our findings reveal for the first time the acute effects of unilateral hippocampal ischemia on ensemble hippocampal neuronal activities.

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Section: Discussionmentioning

confidence: 99%

Changes in Hippocampal Neuronal Activity During and After Unilateral Selective Hippocampal IschemiaIn Vivo

Barth¹,

Módy²

2011

J. Neurosci.

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“…The use of an inhaled coronary vasodilator, if effective and well-tolerated, would greatly simplify the estimation of coronary flow reserve in mice and make the procedure truly noninvasive and amenable to high throughput. Although it is known to lower systemic blood pressure (Zuurbier et al, 2002), isoflurane is now the preferred anesthetic for performing cardiovascular studies in mice because it has minimal effects on heart rate when compared to other nonvolatile agents (Jannsen et al, 2004). However, the ability of isoflurane gas to dilate coronary arteries and increase coronary blood flow is often unrecognized, and the required concentrations and responses are undocumented in mice.…”

Section: Introductionmentioning

confidence: 99%

Effects of Isoflurane on Coronary Blood Flow Velocity in Young, Old and ApoE−/− Mice Measured by Doppler Ultrasound

Hartley

Reddy

Madala

et al. 2007

Ultrasound in Medicine & Biology

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The commonly used anesthetic agent, isoflurane (ISO), is a potent coronary vasodilator which could potentially be used in the assessment of coronary reserve, but its effects on coronary blood flow in mice are unknown. Coronary reserve is reduced by age, coronary artery disease, and other cardiac pathologies in man, and some of these conditions can now be modeled in mice. Accordingly, we used Doppler ultrasound to measure coronary flow velocity in mice anesthetized at low (1%) and at high (2.5%) levels of ISO to generate baseline (B) and elevated hyperemic (H) and Y and between A and O were significant (P < 0.01), while the differences in hyperemic velocities were not (P > 0.05). H/B was higher in old mice due to decreased baseline flow rather than increased hyperemic flow velocity. In contrast ApoE −/− mice have increased baseline and hyperemic velocities perhaps due to coronary lesions. The differences in baseline velocities between young and old mice could be due to age-related changes in basal metabolism or to differential sensitivity to isoflurane. We conclude that Doppler ultrasound combined with coronary vasodilation via isoflurane could provide a convenient and noninvasive method to estimate coronary reserve in mice, but also that care must be taken when assessing coronary flow in mice under isoflurane anesthesia because of its potent coronary vasodilator properties.

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“…has been shown to decrease CI and HR in mice. 20 Koeppen et al 21 have also demonstrated that pentobarbitone significantly reduced renal blood flow. Mechanical ventilation can also affect hemodynamic parameters.…”

Section: Discussionmentioning

confidence: 95%

“…There are reports documenting the effect of anesthetic agents on hemodynamic measurements. 20,21 Pentobarbitone (50 mg kg À1 , i.p.) has been shown to decrease CI and HR in mice.…”

Section: Discussionmentioning

confidence: 99%

Hemodynamics of dexamethasone-induced hypertension in the rat

et al. 2009

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Although dexamethasone (DEX) is known to cause hypertension in humans and in animals, the hemodynamic characteristics of DEX-induced hypertension (DEX-HT) in the rat remain unclear. This study evaluated central and regional hemodynamics, and the role of total peripheral resistance (TPR) using a vasodilator minoxidil. Rats were divided into four groups, namely saline (n¼20), DEX (n¼21), minoxidil+saline (n¼10) and minoxidil+DEX (n¼10). Tail-cuff systolic blood pressure was recorded every second day. After 10-14 days of treatment, central (saline: n¼9, DEX: n¼10) and regional (saline: n¼11, DEX: n¼11) hemodynamic parameters were measured. Central hemodynamic data were also obtained from minoxidil-treated rats. DEX increased blood pressure (Po0.0005) in association with an increase in TPR (Po0.05). However, individual assessments of renal, mesenteric and hindquarter circulations did not detect any significant increase in resistance in these beds. Minoxidil increased cardiac output (P ¢o0.01) and cardiac index (P ¢o0.005) as well as decreased TPR (P¢o0.05) without affecting DEX-HT. DEX prevented weight gain and decreased thymus weight. The increase in TPR in DEX-HT in rats was not simply explained by isolated alterations to resistance in the renal, mesenteric or hindquarter circulations. Minoxidil effectively prevented the increase in TPR but not the increase in blood pressure, suggesting that an increase in TPR is not essential for DEX-induced blood pressure increase. Keywords: dexamethasone; hemodynamics; minoxidil; total peripheral resistance INTRODUCTION Synthetic glucocorticoid dexamethasone (DEX) is commonly used in clinical settings for the treatment of various medical conditions. It is used in adrenal insufficiency as a glucocorticoid hormone replacement treatment, in multiple myeloma together with other chemotherapeutic agents, to decrease cerebral edema due to intracranial pathology and as an anti-emetic in patients with cancer. When used chronically at a supra-physiological dose, DEX results in hypertension. The underlying mechanism for DEX-induced hypertension (DEX-HT) remains unclear. We have recently reviewed postulated mechanisms of DEX-HT. 1 There is evidence against plasma volume expansion 2 or sympathetic nerve activation 3 as key mechanisms of DEX-HT in humans. The roles of endogenous vasoconstrictors and vasodilators in DEX-HT are variable, with possible associations with nitric oxide, prostanoids, angiotensin II, arginine vasopressin, endothelins, catecholamines, neuropeptide Y and atrial natriuretic peptide. 1 Studies on DEX-HT in rodents have indicated that nitric oxide deficiency 4 and oxidative stress 5 are implicated in this form of hypertension. Nevertheless, the hemodynamic profile has not been fully evaluated in this model.The hemodynamics of DEX-HT has been evaluated in both humans 6 and dogs. 7 DEX-HT in humans (3 mg per day) was associated with increased total peripheral resistance (TPR) without any

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Effects of anesthetics on systemic hemodynamics in mice

Cited by 274 publications

References 30 publications

Changes in Hippocampal Neuronal Activity During and After Unilateral Selective Hippocampal IschemiaIn Vivo

Changes in Hippocampal Neuronal Activity During and After Unilateral Selective Hippocampal IschemiaIn Vivo

Effects of Isoflurane on Coronary Blood Flow Velocity in Young, Old and ApoE−/− Mice Measured by Doppler Ultrasound

Hemodynamics of dexamethasone-induced hypertension in the rat

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