Cocaine-induced stroke and hemorrhage in the brain are among the most serious medical complications. The mechanisms underlying these effects are poorly understood but are likely to reflect in part its vasoactive effects that may be exacerbated with repeated drug exposures. Our poor understanding of the cerebrovascular effects of cocaine are due in part to technological limitations in our ability to concurrently assess and thus distinguish cocaine's neuronal effects from its vascular effects. Here we aim to apply our newly developed optical/ fluorescence imaging techniques (OFIs), to study separately the neuronal and cerebrovascular effects of acute and chronic cocaine exposures. OFIs integrate (1) dual-wavelength laser speckle imaging to enable concurrent detection of cerebral blood flow (CBF), blood volume (CBV), and tissue hemoglobin oxygenation (StO2) at high spatiotemporal resolutions across a large field of view, (2) digital-frequency-ramping Doppler optical coherence tomography for in vivo 3D quantitative imaging of the neurovascular network, (3) Rhod2 fluorescence imaging to measure intracellular calcium ([Ca2+]i), and (4) a micro-catheter probe (mOFI) to assess cocaine's effects on subcortical brain regions in real time and at high spatiotemporal resolution. Our pilot study has shown that acute cocaine decreases CBF while increasing deoxyhemoglobin content and increasing intracellular Ca content and that there is sensitization to these effects with repeated exposures. Since increases in intracellular [Ca2+]i are associated with neuronal death following ischemia, we hypothesize that these sensitized responses with chronic cocaine exposures increase the vulnerability of neuronal tissue to damage from hypoxia. To test these hypotheses, we will use OFIs to concurrently measure the effects of acute and chronic cocaine on cerebrovascular responses (CBF, CBV), tissue oxygenation (StO2) and neuronal [Ca2+]i changes in cortical and subcortical brain regions. We will use an animal model of compulsive cocaine self- administration (short and long access) that mimics key aspects of human addiction. In addition, we will examine the efficacy of calcium channel blockers in preventing cocaine-induced increases in intracellular Ca2+ content, as a potential therapeutic strategy to reduce cocaine's cerebrovascular toxicity. We propose the following Specific Aims: Assess the neuronal and vascular effects of acute and chronic cocaine on cortical (using OFI, Aim 1) and subcortical regions (using mOFI, Aim 2);Characterize the 'ischemia-like'neurovascular dysfunction resulting from chronic cocaine exposure (Aim 3), and examine the efficacy of calcium channel blockers to ameliorate cocaine-induced intracellular [Ca2+]i and hemodynamic changes in brain (Aim 4). The proposed studies will provide a better understanding of the mechanisms that underlie cocaine's cerebrovascular toxicity, which could help develop therapeutic interventions to counteract this toxicity. In addition, the proposed studies will introduce an imaging capability that could be applied to studies of the effects of other drugs of abuse and to studies of other brain disorders for which there are pertinent animal models.
Chronic cocaine use damages the brain in several ways: reducing blood flow in the brain, decreasing the oxygen content of the blood for tissue and increasing calcium within individual neurons. Separation of neuronal (calcium content) from vascular (blood flow and oxygenation) effects of cocaine is crucial to understanding the mechanisms that lead to neurovascular toxicity in cocaine abusers. We will apply our newly developed optical tools to investigate the confounding neurotoxic effects of cocaine by simultaneously imaging the neurovascular hemodynamic and intracellular Ca2+ changes at high spatiotemporal resolutions. In addition, we will examine the efficacy of Ca2+-channel blockers to ameliorate neuronal and hemodynamic dysfunction in brain induced by cocaine (e.g., stroke, ischemia).
|Du, Congwu; Volkow, Nora D; You, Jiang et al. (2018) Cocaine-induced ischemia in prefrontal cortex is associated with escalation of cocaine intake in rodents. Mol Psychiatry :|
|Li, Ang; Zeng, Guang; Du, Congwu et al. (2018) Automated motion-artifact correction in an OCTA image using tensor voting approach. Appl Phys Lett 113:101102|
|Gu, Xiaochun; Chen, Wei; You, Jiang et al. (2018) Long-term optical imaging of neurovascular coupling in mouse cortex using GCaMP6f and intrinsic hemodynamic signals. Neuroimage 165:251-264|
|Allen, Craig P; Park, Kicheon; Li, Ang et al. (2018) Enhanced neuronal and blunted hemodynamic reactivity to cocaine in the prefrontal cortex following extended cocaine access: optical imaging study in anesthetized rats. Addict Biol :|
|Li, Ang; You, Jiang; Du, Congwu et al. (2017) Automated segmentation and quantification of OCT angiography for tracking angiogenesis progression. Biomed Opt Express 8:5604-5616|
|You, Jiang; Li, Ang; Du, Congwu et al. (2017) Volumetric Doppler angle correction for ultrahigh-resolution optical coherence Doppler tomography. Appl Phys Lett 110:011102|
|Yin, Wei; Clare, Kevin; Zhang, Qiujia et al. (2017) Chronic cocaine induces HIF-VEGF pathway activation along with angiogenesis in the brain. PLoS One 12:e0175499|
|Chen, Wei; Park, Kicheon; Volkow, Nora et al. (2016) Cocaine-Induced Abnormal Cerebral Hemodynamic Responses to Forepaw Stimulation Assessed by Integrated Multi-wavelength Spectroimaging and Laser Speckle Contrast Imaging. IEEE J Sel Top Quantum Electron 22:|
|Chen, W; Liu, P; Volkow, N D et al. (2016) Cocaine attenuates blood flow but not neuronal responses to stimulation while preserving neurovascular coupling for resting brain activity. Mol Psychiatry 21:1408-16|
|Zhang, Qiujia; You, Jiang; Volkow, Nora D et al. (2016) Chronic cocaine disrupts neurovascular networks and cerebral function: optical imaging studies in rodents. J Biomed Opt 21:26006|
Showing the most recent 10 out of 23 publications