Procedure for minimizing stress for fMRI studies in conscious rats

King, Jean A.; Garelick, Timothy S.; Brevard, Mathew E.; Chen, Wei; Messenger, Tara L.; Duong, Timothy Q.; Ferris, Craig F.

doi:10.1016/j.jneumeth.2005.04.011

Cited by 204 publications

(224 citation statements)

References 23 publications

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“…A detailed investigation of acclimation and restraint effects has been described elsewhere (King et al, 2005). In this study, blood gases, heart rate, respiration rate, and mean arterial blood pressure in the awake animals were within normal physiological ranges, and the number of struggling movements markedly decreased after the first hour of being awake in the restrainer.…”

Section: Potential Issuesmentioning

confidence: 51%

Cerebral blood flow and BOLD fMRI responses to hypoxia in awake and anesthetized rats

Duong

2007

Brain Research

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This study investigated the functional MRI responses to graded hypoxia in awake/restrained and anesthetized animals by measuring cerebral blood flow (CBF) and blood oxygenation (BOLD) changes and estimating changes in cerebral metabolic rate of oxygen (CMRO 2 ). Hypoxia in isoflurane anesthetized rats reduced blood pressure but did not change heart rate and respiration rate. In contrast, hypoxia in awake animals showed compensatory responses by sustaining blood pressure, increasing heart rate and respiration rate. Basal CBF was higher under isoflurane anesthesia than awake state because isoflurane is a vasodilator. Graded hypoxia decreased BOLD signals. Surprisingly, hypoxia also decreased CBF likely because hypoxia induced hypocapnia. Hypoxiainduced CBF and BOLD decreases were smaller in awake, relative to anesthetized, rats at low pO 2 , but similar at high pO 2 . CBF leveled off with decreasing hypoxia-induced pCO 2 in awake rats, but monotonically decreased in anesthetized rats. CMRO 2 estimated using a biophysical BOLD model did not change under mild hypoxia but was reduced under severe hypoxia relative to baseline. These results showed that isoflurane attenuated automomic responses to hypoxia, hypoxia-induced hypocapnia dominated CBF changes, tissues in awake conditions appeared better oxygenated, and severe hypoxia reduced oxygen metabolism. This study underscored the marked differences in BOLD and CBF MRI responses to hypoxia in vivo between awake and anesthetized conditions and has implications for functional MRI studies of hypoxia in anesthetized animal models.

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Section: Potential Issuesmentioning

confidence: 51%

Cerebral blood flow and BOLD fMRI responses to hypoxia in awake and anesthetized rats

Duong

2007

Brain Research

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“…This procedure was repeated over three consecutive days. Results obtained from our laboratory indicate that this procedure improves contrast-to-noise and signal-to-noise ratios because of reduced motor episodes during imaging sessions (King et al, 2005).…”

Section: Methodsmentioning

confidence: 88%

Functional Magnetic Resonance Imaging Shows Oxytocin Activates Brain Regions Associated with Mother–Pup Bonding during Suckling

Febo¹,

Numan²,

Ferris³

2005

J. Neurosci.

178

153

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Oxytocin is released in the maternal brain during breastfeeding and may help strengthen the mother-infant relationship. Here, we used functional magnetic resonance imaging to determine whether oxytocin modulates brain activity in postpartum day 4 -8 dams receiving suckling stimulation. During imaging sessions, dams were exposed to pup suckling before and after administration of an oxytocin receptor antagonist. Another group of dams received oxytocin alone. Changes in brain activation in response to suckling closely matched that elicited by oxytocin administration. The overlapping brain areas included the olfactory system, nucleus accumbens, insular cortex, prefrontal cortex, ventral tegmental area, cortical amygdala, and several cortical and hypothalamic nuclei. Blockade of oxytocin receptors largely attenuated activation in these regions. The data suggest that oxytocin may strengthen mother-infant bond formation partly by acting through brain areas involved in regulating olfactory discrimination, emotions, and reward.

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“…Chronic restraint stress during pregnancy in rats increases maternal care and anxiety and decreases maternal aggression in some studies 5, but decreases maternal care in others 6 . Restraint stress is a potent physical stressor 7, and some reports are inconsistent with the attenuated maternal care observed in human mothers with postpartum depression 4 . Prenatal ultramild stress does not affect pup care, but does reduce maternal aggression 8 .…”

Section: Introductionmentioning

confidence: 99%

Using Chronic Social Stress to Model Postpartum Depression in Lactating Rodents

Carini

Murgatroyd

Nephew

2013

JoVE

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Exposure to chronic stress is a reliable predictor of depressive disorders, and social stress is a common ethologically relevant stressor in both animals and humans. However, many animal models of depression were developed in males and are not applicable or effective in studies of postpartum females. Recent studies have reported significant effects of chronic social stress during lactation, an ethologically relevant and effective stressor, on maternal behavior, growth, and behavioral neuroendocrinology. This manuscript will describe this chronic social stress paradigm using repeated exposure of a lactating dam to a novel male intruder, and the assessment of the behavioral, physiological, and neuroendocrine effects of this model. Chronic social stress (CSS) is a valuable model for studying the effects of stress on the behavior and physiology of the dam as well as her offspring and future generations. The exposure of pups to CSS can also be used as an early life stress that has long term effects on behavior, physiology, and neuroendocrinology.

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Procedure for minimizing stress for fMRI studies in conscious rats

Cited by 204 publications

References 23 publications

Cerebral blood flow and BOLD fMRI responses to hypoxia in awake and anesthetized rats

Cerebral blood flow and BOLD fMRI responses to hypoxia in awake and anesthetized rats

Functional Magnetic Resonance Imaging Shows Oxytocin Activates Brain Regions Associated with Mother–Pup Bonding during Suckling

Using Chronic Social Stress to Model Postpartum Depression in Lactating Rodents

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