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Jerem P, Romero LM. It's cool to be stressed: body surface temperatures track sympathetic nervous system activation during acute stress. J Exp Biol 2023; 226:jeb246552. [PMID: 37767773 PMCID: PMC10629684 DOI: 10.1242/jeb.246552] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 09/24/2023] [Indexed: 09/29/2023]
Abstract
The acute stress response can be considered the primary evolutionary adaptation to maximise fitness in the face of unpredictable environmental challenges. However, the difficulties of assessing physiology in natural environments mean that comparatively little is known about how response variation influences fitness in free-living animals. Currently, determining acute stress physiology typically involves blood sampling or cardiac monitoring. Both require trapping and handling, interrupting natural behaviour, and potentially biasing our understanding toward trappable species/individuals. Importantly, limits on repeated sampling also restrict response phenotype characterisation, vital for linking stress with fitness. Surface temperature dynamics resulting from peripheral vasomotor activity during acute stress are increasingly promoted as alternative physiological stress indicators, which can be measured non-invasively using infrared thermal imaging, overcoming many limitations of current methods. Nonetheless, which aspects of stress physiology they represent remains unclear, as the underlying mechanisms are unknown. To date, validations have primarily targeted the hypothalamic-pituitary-adrenal axis, when the sympathetic-adrenal-medullary (SAM) system is likely the primary driver of vasomotor activity during acute stress. To address this deficit, we compared eye and bill region surface temperatures (measured using thermal imaging) with SAM system activity (measured as heart rate variability via electrocardiogram telemetry) in wild-caught captive house sparrows (Passer domesticus) during capture and handling. We found that lower body surface temperatures were associated with increased sympathetic nervous system activation. Consequently, our data confirm that body surface temperatures can act as a proxy for sympathetic activation during acute stress, providing potentially transformative opportunities for linking the acute stress response with fitness in the wild.
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Affiliation(s)
- Paul Jerem
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9700 CC Groningen, The Netherlands
- Department of Biology, Tufts University, Medford, MA 02155, USA
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Lezama-García K, Mota-Rojas D, Martínez-Burnes J, Villanueva-García D, Domínguez-Oliva A, Gómez-Prado J, Mora-Medina P, Casas-Alvarado A, Olmos-Hernández A, Soto P, Muns R. Strategies for Hypothermia Compensation in Altricial and Precocial Newborn Mammals and Their Monitoring by Infrared Thermography. Vet Sci 2022; 9:vetsci9050246. [PMID: 35622774 PMCID: PMC9145389 DOI: 10.3390/vetsci9050246] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 05/18/2022] [Accepted: 05/18/2022] [Indexed: 02/06/2023] Open
Abstract
Thermoregulation in newborn mammals is an essential species-specific mechanism of the nervous system that contributes to their survival during the first hours and days of their life. When exposed to cold weather, which is a risk factor associated with mortality in neonates, pathways such as the hypothalamic–pituitary–adrenal axis (HPA) are activated to achieve temperature control, increasing the circulating levels of catecholamine and cortisol. Consequently, alterations in blood circulation and mechanisms to produce or to retain heat (e.g., vasoconstriction, piloerection, shivering, brown adipocyte tissue activation, and huddling) begin to prevent hypothermia. This study aimed to discuss the mechanisms of thermoregulation in newborn domestic mammals, highlighting the differences between altricial and precocial species. The processes that employ brown adipocyte tissue, shivering, thermoregulatory behaviors, and dermal vasomotor control will be analyzed to understand the physiology and the importance of implementing techniques to promote thermoregulation and survival in the critical post-birth period of mammals. Also, infrared thermography as a helpful method to perform thermal measurements without animal interactions does not affect these parameters.
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Affiliation(s)
- Karina Lezama-García
- PhD Program in Biological and Health Sciences [Doctorado en Ciencias Biológicas y de la Salud], Universidad Autónoma Metropolitana (UAM), Mexico City 04960, Mexico;
| | - Daniel Mota-Rojas
- Neurophysiology, Behavior and Animal Welfare Assessment, DPAA, Universidad Autónoma Metropolitana (UAM), Mexico City 04960, Mexico; (A.D.-O.); (J.G.-P.); (A.C.-A.); (P.S.)
- Correspondence:
| | - Julio Martínez-Burnes
- Animal Health Group, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Tamaulipas, Victoria City 87000, Tamaulipas, Mexico;
| | - Dina Villanueva-García
- Division of Neonatology, National Institute of Health, Hospital Infantil de México Federico Gómez, Doctor Márquez 162, Mexico City 06720, Mexico;
| | - Adriana Domínguez-Oliva
- Neurophysiology, Behavior and Animal Welfare Assessment, DPAA, Universidad Autónoma Metropolitana (UAM), Mexico City 04960, Mexico; (A.D.-O.); (J.G.-P.); (A.C.-A.); (P.S.)
| | - Jocelyn Gómez-Prado
- Neurophysiology, Behavior and Animal Welfare Assessment, DPAA, Universidad Autónoma Metropolitana (UAM), Mexico City 04960, Mexico; (A.D.-O.); (J.G.-P.); (A.C.-A.); (P.S.)
| | - Patricia Mora-Medina
- Department of Livestock Science, FESC, Universidad Nacional Autónoma de México (UNAM), Cuautitlán Izcalli 54714, Mexico;
| | - Alejandro Casas-Alvarado
- Neurophysiology, Behavior and Animal Welfare Assessment, DPAA, Universidad Autónoma Metropolitana (UAM), Mexico City 04960, Mexico; (A.D.-O.); (J.G.-P.); (A.C.-A.); (P.S.)
| | - Adriana Olmos-Hernández
- Division of Biotechnology—Bioterio and Experimental Surgery, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra (INR-LGII), Mexico City 14389, Mexico;
| | - Paola Soto
- Neurophysiology, Behavior and Animal Welfare Assessment, DPAA, Universidad Autónoma Metropolitana (UAM), Mexico City 04960, Mexico; (A.D.-O.); (J.G.-P.); (A.C.-A.); (P.S.)
| | - Ramon Muns
- Agri-Food and Biosciences Institute, Livestock Production Sciences Unit, Hillsborough BT26 6DR, Northern Ireland, UK;
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Curay CM, Irwin MR, Kiyatkin EA. Rapid fluctuations in brain oxygenation during glucose-drinking behavior in trained rats. J Neurophysiol 2022; 127:384-392. [PMID: 35044849 PMCID: PMC8799397 DOI: 10.1152/jn.00527.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Proper inflow of oxygen into brain tissue is essential for maintaining normal neural functions. Although oxygen levels in the brain's extracellular space depend upon a balance between its delivery from arterial blood and its metabolic consumption, the use of high-speed electrochemical detection revealed rapid increases in brain oxygen levels elicited by various salient sensory stimuli. These stimuli also increase intrabrain heat production, an index of metabolic neural activation, but these changes are slower and more prolonged than changes in oxygen levels. Therefore, under physiological conditions, the oxygen inflow into brain tissue exceeds its loss due to consumption, thus preventing any metabolic deficit. Here, we used oxygen sensors coupled with amperometry to examine the pattern of real-time oxygen fluctuations in the nucleus accumbens during glucose-drinking behavior in trained rats. Following the exposure to a glucose-containing cup, oxygen levels rapidly increased, peaked when the rat initiated drinking, and relatively decreased during consumption. Similar oxygen changes but more episodic drinking occurred when Stevia, a calorie-free sweet substance, was substituted for glucose. When water was substituted for glucose, rats tested the water but refused to consume all of it. Although the basic pattern of oxygen changes during this water test was similar to that with glucose drinking, the increases were larger. Finally, oxygen increases were significantly larger when rats were exposed to concealed glucose and made multiple unsuccessful attempts to obtain and consume it. Based on these data, we discuss the mechanisms underlying behavior-related brain oxygen fluctuations and their functional significance.NEW & NOTEWORTHY Oxygen sensors coupled with high-speed amperometry were used to examine brain oxygen fluctuations during glucose-drinking behavior in trained rats. Oxygen levels rapidly increased following presentation of a glucose-contained cup, peaking at the initiation of glucose drinking, and relatively decreasing during drinking. Oxygen increases were larger when rats were exposed to concealed glucose and made multiple attempts to obtain it. We discuss the mechanisms underlying behavior-related brain oxygen fluctuations and their functional significance.
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Affiliation(s)
- Carlos M. Curay
- Behavioral Neuroscience Branch, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, DHHS, Baltimore, Maryland
| | - Matthew R. Irwin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, DHHS, Baltimore, Maryland
| | - Eugene A. Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, DHHS, Baltimore, Maryland
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Relationships between oxygen changes in the brain and periphery following physiological activation and the actions of heroin and cocaine. Sci Rep 2021; 11:6355. [PMID: 33737657 PMCID: PMC7973713 DOI: 10.1038/s41598-021-85798-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/05/2021] [Indexed: 11/09/2022] Open
Abstract
Using two-sensor electrochemical recordings in freely moving rats, we examined the relationship between physiological and drug-induced oxygen fluctuations in the brain and periphery. Animals chronically implanted with oxygen sensors in the nucleus accumbens (NAc) and subcutaneous (SC) space were subjected to several mildly arousing stimuli (sound, tail-pinch and social interaction) and intravenous injections of cocaine and heroin. Arousing stimuli induced rapid increases in NAc oxygen levels followed by and correlated with oxygen decreases in the SC space. Therefore, cerebral vasodilation that increases cerebral blood flow and oxygen entry into brain tissue results from both direct neuronal activation and peripheral vasoconstriction, which redistributes arterial blood from periphery to the brain. The latter factor could also explain a similar pattern of oxygen responses found in the substantia nigra reticulata, suggesting hyperoxia as a global phenomenon with minor structural differences during early time intervals following the stimulus onset. While arousing stimuli and cocaine induced similar oxygen responses in the brain and SC space, heroin induced a biphasic down-up brain oxygen fluctuation associated with a monophasic oxygen decrease in the SC space. Oxygen decreases occurred more rapidly and stronger in the SC space, reflecting a drop in blood oxygen levels due to respiratory depression.
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Kiyatkin EA. Brain temperature and its role in physiology and pathophysiology: Lessons from 20 years of thermorecording. Temperature (Austin) 2019; 6:271-333. [PMID: 31934603 PMCID: PMC6949027 DOI: 10.1080/23328940.2019.1691896] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 10/29/2019] [Accepted: 10/30/2019] [Indexed: 12/11/2022] Open
Abstract
It is well known that temperature affects the dynamics of all physicochemical processes governing neural activity. It is also known that the brain has high levels of metabolic activity, and all energy used for brain metabolism is finally transformed into heat. However, the issue of brain temperature as a factor reflecting neural activity and affecting various neural functions remains in the shadow and is usually ignored by most physiologists and neuroscientists. Data presented in this review demonstrate that brain temperature is not stable, showing relatively large fluctuations (2-4°C) within the normal physiological and behavioral continuum. I consider the mechanisms underlying these fluctuations and discuss brain thermorecording as an important tool to assess basic changes in neural activity associated with different natural (sexual, drinking, eating) and drug-induced motivated behaviors. I also consider how naturally occurring changes in brain temperature affect neural activity, various homeostatic parameters, and the structural integrity of brain cells as well as the results of neurochemical evaluations conducted in awake animals. While physiological hyperthermia appears to be adaptive, enhancing the efficiency of neural functions, under specific environmental conditions and following exposure to certain psychoactive drugs, brain temperature could exceed its upper limits, resulting in multiple brain abnormalities and life-threatening health complications.
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Affiliation(s)
- Eugene A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
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Deipolyi AR, Czaplicki CD, Oklu R. Inflammatory and infectious aortic diseases. Cardiovasc Diagn Ther 2018; 8:S61-S70. [PMID: 29850419 PMCID: PMC5949581 DOI: 10.21037/cdt.2017.09.03] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 09/01/2017] [Indexed: 12/15/2022]
Abstract
Aortitis is aortic inflammation, which can be due to inflammatory or infectious diseases. Left undiagnosed, aortitis can lead to aneurysm formation and rupture, in addition to ischemic compromise of major organs. Infectious aortic diseases include mycotic aneurysm and graft infection; the most common inflammatory diseases are Takayasu's and giant cell arteritis. We review the epidemiology, etiology, presentation and diagnosis, and treatment of these entities.
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Affiliation(s)
- Amy R. Deipolyi
- Interventional Radiology Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | | | - Rahmi Oklu
- Division of Vascular & Interventional Radiology, Mayo Clinic, Phoenix, AZ, USA
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Kiyatkin EA. Brain temperature: from physiology and pharmacology to neuropathology. HANDBOOK OF CLINICAL NEUROLOGY 2018; 157:483-504. [DOI: 10.1016/b978-0-444-64074-1.00030-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Deipolyi AR, Rho J, Khademhosseini A, Oklu R. Diagnosis and management of mycotic aneurysms. Clin Imaging 2016; 40:256-62. [DOI: 10.1016/j.clinimag.2015.11.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 11/04/2015] [Accepted: 11/23/2015] [Indexed: 02/06/2023]
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Kiyatkin EA, Lenoir M. Intravenous saline injection as an interoceptive signal in rats. Psychopharmacology (Berl) 2011; 217:387-96. [PMID: 21494787 PMCID: PMC3377945 DOI: 10.1007/s00213-011-2294-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 03/28/2011] [Indexed: 10/18/2022]
Abstract
RATIONALE Addictive drugs are commonly delivered in the organism by means of intravenous (i.v.) injections. Since saline mimics the blood environment by basic ionic properties and pH, it is generally assumed that it should not have any physiological effects, serving as a control for the effects induced by drugs. OBJECTIVE The aim of the study was to examine central, behavioral, and physiological effects of stress- and cue-free i.v. saline injection in freely moving rats. METHODS We examined how a typical low-volume and slow-speed saline injections affect cortical electroencephalograpy (EEG), neck electromyography (EMG), locomotor activity as well as central and peripheral temperatures. RESULTS Saline injection made during slow-wave synchronized activity induces rapid transient EEG desynchronization, manifesting as a drop of EEG total power, decrease in alpha activity, and increases in beta and gamma activities. Saline injection did not affect locomotor activity as well as brain and body temperatures, but induced a transient increase in neck EMG activity and a rapid brief drop in skin temperature, suggesting peripheral vasoconstriction. These responses were virtually fully absent when saline injection was made during naturally occurring desynchronized EEG activity during behavioral activity. CONCLUSIONS Since i.v. injection is able to produce a peripheral sensory signal that is transmitted rapidly to the CNS and followed by a more prolonged effect of the injected drug on brain cells, with repeated drug administrations, the injection itself could play a role of drug-related sensory cue, thus inducing conditioned physiological responses and altering the effects of injected drugs.
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Affiliation(s)
- Eugene A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, MD 21224, USA.
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Kiyatkin EA. Differential effects of dopamine and opioid receptor blockade on motivated Coca-Cola drinking behavior and associated changes in brain, skin and muscle temperatures. Neuroscience 2010; 167:439-55. [PMID: 20167257 DOI: 10.1016/j.neuroscience.2010.02.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 02/10/2010] [Accepted: 02/11/2010] [Indexed: 10/19/2022]
Abstract
Although pharmacological blockade of both dopamine (DA) and opiate receptors has an inhibiting effect on appetitive motivated behaviors, it is still unclear which physiological mechanisms affected by these treatments underlie the behavioral deficit. To clarify this issue, we examined how pharmacological blockade of either DA (SCH23390+eticlopride at 0.2 mg/kg each) or opioid receptors (naloxone 1 mg/kg) affects motor activity and temperature fluctuations in the nucleus accumbens (NAcc), temporal muscle, and facial skin associated with motivated Coca-Cola drinking behavior in rats. In drug-free conditions, presentation of a cup containing 5 ml of Coca-Cola induced locomotor activation and rapid NAcc temperature increases, which both transiently decreased during drinking, and phasically increased again after the cup was emptied. Muscle temperatures followed this pattern, but increases were weaker and more delayed than those in the NAcc. Skin temperature rapidly dropped after cup presentation, remained at low levels during consumption, and slowly restored during post-consumption behavioral activation. By itself, DA receptor blockade induced robust decrease in spontaneous locomotion, moderate increases in brain and muscle temperatures, and a relative increase in skin temperatures, suggesting metabolic activation coupled with adynamia. Following this treatment (approximately 180 min), motor activation to cup presentation and Coca-Cola consumption were absent, but rats showed NAcc and muscle temperature increases following cup presentation comparable to control. Therefore, DA receptor blockade does not affect significantly central and peripheral autonomic responses to appetitive stimuli, but eliminates their behavior-activating effects, thus disrupting appetitive behavior and blocking consumption. Naloxone alone slightly decreased brain and muscle temperatures and increased skin temperatures, pointing at the enhanced heat loss and possible minor inhibition of basal metabolic activity. This treatment (approximately 60 min) had minimal effects on the latencies of drinking, but increased its total duration, with licking interrupted by pauses and retreats. This behavioral attenuation was coupled with weaker than in control locomotor activation and diminished temperature fluctuations in each recording location. Therefore, attenuation of normal behavioral and physiological responses to appetitive stimuli appears to underlie modest inhibiting effects of opiate receptor blockade on motivated behavior and consumption.
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Affiliation(s)
- E A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, MD 21224, USA.
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Smirnov MS, Kiyatkin EA, Smith Y. Cocaine action on peripheral, non-monoamine neural substrates as a trigger of electroencephalographic desynchronization and electromyographic activation following i.v. administration in freely moving rats. Neuroscience 2010; 165:500-14. [PMID: 19861149 PMCID: PMC2794948 DOI: 10.1016/j.neuroscience.2009.10.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 09/22/2009] [Accepted: 10/16/2009] [Indexed: 11/30/2022]
Abstract
Many important physiological, behavioral and subjective effects of i.v. cocaine (COC) are exceptionally rapid and transient, suggesting a possible involvement of peripheral neural substrates in their triggering. In the present study, we used high-speed electroencephalographic (EEG) and electromyographic (EMG) recordings (4-s resolution) in freely moving rats to characterize the central electrophysiological effects of i.v. COC at low doses within a self-administration range (0.25-1.0 mg/kg). We found that COC induces rapid, strong, and prolonged desynchronization of cortical EEG (decrease in alpha and increase in beta and gamma activity) and activation of the neck EMG that begin within 2-6 s following the start of a 10-s injection; immediate components of both effects were dose-independent. The rapid effects of COC were mimicked by i.v. COC methiodide (COC-MET), a derivative that cannot cross the blood-brain barrier. At equimolar doses (0.33-1.33 mg/kg), COC-MET had equally fast and strong effects on EEG and EMG total powers, decreasing alpha and increasing beta and gamma activities. Rapid EEG desynchronization and EMG activation was also induced by i.v. procaine, a structurally similar, short-acting local anesthetic with virtually no effects on monoamine uptake; at equipotential doses (1.25-5.0 mg/kg), these effects were weaker and shorter in duration than those of COC. Surprisingly, i.v. saline injection delivered during slow-wave sleep (but not during quiet wakefulness) also induced a transient EEG desynchronization but without changes in EMG and motor activity; these effects were significantly weaker and much shorter than those induced by all tested drugs. These data suggest that in awake animals, i.v. COC induces rapid cortical activation and a subsequent motor response via its action on peripheral non-monoamine neural elements, involving neural transmission via visceral sensory pathways. By providing a rapid neural signal and triggering neural activation, such an action might play a crucial role in the sensory effects of COC, thus contributing to the learning and development of drug-taking behavior.
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Affiliation(s)
- Michael S. Smirnov
- Behavioral Neuroscience Branch, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, Maryland 21224
| | - Eugene A. Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, Maryland 21224
| | - Y. Smith
- Behavioral Neuroscience Branch, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, Maryland 21224
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Kiyatkin EA, Smirnov MS. Rapid EEG desynchronization and EMG activation induced by intravenous cocaine in freely moving rats: a peripheral, nondopamine neural triggering. Am J Physiol Regul Integr Comp Physiol 2009; 298:R285-300. [PMID: 19939972 DOI: 10.1152/ajpregu.00628.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many important physiological, behavioral, and psychoemotional effects of intravenous (IV) cocaine (COC) are too fast and transient compared with pharmacokinetic predictions, suggesting a possible involvement of peripheral neural mechanisms in their triggering. In the present study, we examined changes in cortical electroencephalogram (EEG) and neck electromyogram (EMG) induced in freely moving rats by IV COC administration at low, reinforcing doses (0.25-1.0 mg/kg) and compared them with those induced by an auditory stimulus and IV COC methiodide, which cannot cross the blood-brain barrier. We found that COC induces rapid, strong, and prolonged EEG desynchronization, associated with decrease in alpha and increase in beta and gamma activities, and EMG activation and that both begin within 2-6 s following the start of a 10-s injection; immediate components of this effect were dose independent. The rapid COC-induced changes in EEG and EMG resembled those induced by an auditory stimulus; the latter effects had shorter onset latencies and durations and were fully blocked during urethane anesthesia. Although urethane anesthesia completely blocked COC-induced EMG activation and rapid components of EEG response, COC still induced EEG desynchronization that was much weaker, greatly delayed (approximately 60 s), and associated with tonic decreases in delta and increases in alpha, beta, and gamma activities. Surprisingly, IV saline delivered during slow-wave sleep (but not quite wakefulness) also induced a transient EEG desynchronization but without changes in EMG activity; these effects were also fully blocked during anesthesia. Peripherally acting COC methiodide fully mimicked rapid EEG and EMG effects of regular COC, but the effects at an equimolar dose were less prolonged than those with regular COC. These data suggest that in awake animals IV COC, like somato-sensory stimuli, induces cortical activation and a subsequent motor response via its action on peripheral neural elements and involving rapid neural transmission. By providing a rapid neural signal and triggering transient neural activation, such an action might play a crucial role in the sensory effects of COC, thus contributing to the learning and development of drug-taking behavior.
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Affiliation(s)
- Eugene A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Dr., Baltimore, MD 21224, USA.
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Smirnov MS, Kiyatkin EA. Phasic and tonic fluctuations in brain, muscle, and skin temperatures during motivated drinking behavior in rats: physiological correlates of motivation and reward. Brain Res 2009; 1310:87-102. [PMID: 19932691 DOI: 10.1016/j.brainres.2009.11.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 11/15/2009] [Accepted: 11/17/2009] [Indexed: 10/20/2022]
Abstract
Since brain metabolism is accompanied by heat production, measurement of brain temperature offers a method for assessing global alterations in metabolic neural activity. This approach, high-resolution (5-s bin) temperature recording from the nucleus accumbens (NAcc), temporal muscle, and facial skin, was used to study motivated drinking behavior in rats. Experienced animals were presented with a cup containing 5-ml of Coca-Cola(R) (Coke) beverage that resulted, within certain latencies, in initiation of a continuous chain of licking until all liquid was fully consumed. While cup presentation induced rapid, gradual NAcc temperature increase peaking at the start of drinking, temperatures slowly decreased during Coke consumption, but phasically increased again in the post-consumption period when rats were hyperactive, showing multiple interactions with an empty cup. Muscle temperatures followed a similar pattern, but the changes were weaker and delayed compared to those in the brain. Skin temperature rapidly dropped after cup presentation, steadily maintained at low levels during consumption, and slowly restored during the post-consumption period. Substitution of the expected Coke with either sugar-free Diet Coke(R) or water resulted in numerous drinking attempts but ultimately no consumption. During these tests, locomotor activation was much greater and more prolonged, brain and muscle temperatures increased monophasically, and their elevation was significantly greater than that with regular Coke tests. Food deprivation decreased drinking latencies, did not change the pattern of temperature fluctuations during Coke consumption, but temperature elevations were greater than in controls. Our data suggest sustained neural activation triggered by appetitive stimuli and associated with activational (seeking) aspects of appetitive motivated behavior. This seeking-related activation is rapidly ceased following consumption, suggesting this change as a neural correlate of reward. In contrast, inability to obtain an expected reward maintains neural activation and seeking behavior, resulting in larger deviations in physiological parameters.
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Affiliation(s)
- Michael S Smirnov
- Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, DHHS, 333 Cassell Drive, Baltimore, MD 21224, USA
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Smirnov MS, Kiyatkin EA. Fluctuations in central and peripheral temperatures associated with feeding behavior in rats. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1415-24. [PMID: 18799633 DOI: 10.1152/ajpregu.90636.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the pattern of temperature fluctuations in the nucleus accumbens (NAcc), temporal muscle, and skin, along with locomotion in food-deprived and nondeprived rats following the presentation of an open or closed food container and during subsequent eating or food-seeking behavior without eating. Although rats in food-deprived, quiet resting conditions had more than twofold lower spontaneous locomotion and lower temperature values than in nondeprived conditions, after presentation of a container, they consistently displayed food-seeking behavior, showing much larger and longer temperature changes. When the container was open, rats rapidly retrieved food and consumed it. Food consumption was preceded and accompanied by gradual increases in brain and muscle temperatures ( approximately 1.5 degrees C) and a weaker, delayed increase in skin temperature ( approximately 0.8 degrees C). All temperatures began to rapidly fall immediately after eating was completed, but NAcc and muscle temperatures returned to baseline after approximately 35 min. When the container was closed and rats were unable to obtain food, they continued food-seeking activity during the entire period of presentation. Similar to eating, this activity was preceded and accompanied by gradual temperature increases in the brain and muscle, which were somewhat smaller than those during eating ( approximately 1.2 degrees C), with no changes in skin temperature. In contrast to trials with eating, NAcc and muscle temperatures continued to increase for approximately 10 min after the container was removed from the cage and the rat continued food-seeking behavior, with a return to baselines after approximately 50 min. These temperature fluctuations are discussed with respect to alterations in metabolic brain activity associated with feeding behavior, depending upon deprivation state and food availability.
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Affiliation(s)
- Michael S Smirnov
- Behavioral Neuroscience Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, DHHS, 5500 Nathan Shock Drive, Baltimore, Maryland 21224, USA
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Brain temperature responses to salient stimuli persist during dopamine receptor blockade despite a blockade of locomotor responses. Pharmacol Biochem Behav 2008; 91:233-42. [PMID: 18727935 DOI: 10.1016/j.pbb.2008.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 08/01/2008] [Accepted: 08/04/2008] [Indexed: 11/23/2022]
Abstract
We examined how an acute dopamine (DA) receptor blockade affects locomotor and brain (nucleus accumbens or NAcc), muscle and skin temperature responses to three arousing stimuli (procedure of sc injection, tail-pinch and social interaction with another male rat) and intravenous cocaine (1 mg/kg). DA receptor blockade was induced by mixture of D1- (SCH23390) and D-2 selective (eticlopride) DA antagonists at 0.2 mg/kg doses. Each arousing stimulus and cocaine caused locomotor activation, prolonged increase in NAcc and muscle temperature (0.6-1.0 degrees C for 20-50 min) and transient skin hypothermia (-0.6 degrees C for 1-3 min) in drug-naive conditions. DA receptor blockade strongly decreased basal locomotor activity, but moderately increased brain, muscle and skin temperatures. Therefore, selective interruption of DA transmission does not inhibit the brain, making it more metabolically active and warmer despite skin vasodilatation and the enhanced heat loss to the body and the external environment. DA antagonists strongly decreased locomotor responses to all stimuli and cocaine, had no effects on acute skin vasoconstriction, but differentially affected stimuli- and drug-induced changes in NAcc and muscle temperatures. While brain and muscle temperatures induced by cocaine were fully blocked and both temperatures slightly decreased, temperature increases induced by tail-pinch and social interaction, despite a significant attenuation, persisted during DA receptor blockade. These data are discussed to define the role of the DA system in regulating the central activation processes and behavioral responsiveness to natural arousing and drug stimuli.
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Smirnov MS, Kiyatkin EA. Behavioral and temperature effects of delta 9-tetrahydrocannabinol in human-relevant doses in rats. Brain Res 2008; 1228:145-60. [PMID: 18619424 DOI: 10.1016/j.brainres.2008.06.069] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 06/19/2008] [Accepted: 06/19/2008] [Indexed: 10/21/2022]
Abstract
Marijuana smoking dramatically alters responses to various environmental stimuli. To study this phenomenon, we assessed how delta-9-tetrahydrocannabinol (THC), a primary psychoactive ingredient of marijuana, affects locomotor and brain (nucleus accumbens or NAcc), muscle and skin temperature responses to natural arousing stimuli (one-minute tail-pinch and one-minute social interaction with another male rat) and iv cocaine (1 mg/kg) in male rats. THC was administered at three widely varying doses (0.5, 2.0 and 8.0 mg/kg, ip), and the drug-induced changes in basal values and responses to stimuli were compared to those occurring following ip vehicle injections (control). Each stimulus in control conditions caused acute locomotor activation, a prolonged increase in brain and muscle temperature (0.6-1.0 degrees C for 20-50 min) and transient decrease in skin temperature (-0.6 degrees C for 1-3 min). While THC at any dose had a tendency to decrease spontaneous locomotion as well as brain and muscle temperatures, true hypothermia and hypoactivity as well as clearly diminished locomotor and temperature responses to all stimuli were only seen following the largest dose. In this case, temperature decreases in the NAcc were stronger than in the muscle, suggesting metabolic brain inhibition as the primary cause of hypoactivity, hypothermia and hyporesponsiveness. While weaker in strength and without associated vasodilatation, this response pattern is mimicked by general anesthetics, questioning to what extent the hypothermic action of THC is specific (i.e., mediated via endogenous cannabinoid receptors) or non-specific, reflecting drug interaction with membrane lipids or other receptors. In contrast, weaker behavioral and temperature effects of THC at lower doses resemble those of diazepam, whose locomotion- and temperature-decreasing effects are evident only in activated conditions, when rats are moving and basal temperatures are elevated.
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Affiliation(s)
- Michael S Smirnov
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS Baltimore, Maryland 21224, USA
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Kiyatkin EA, Bae D. Behavioral and brain temperature responses to salient environmental stimuli and intravenous cocaine in rats: effects of diazepam. Psychopharmacology (Berl) 2008; 196:343-56. [PMID: 17938891 DOI: 10.1007/s00213-007-0965-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Accepted: 09/20/2007] [Indexed: 11/26/2022]
Abstract
RATIONALE While diazepam is an effective anxiolytic and somnolent drug in humans, its physiological and behavioral effects in animals are often variable. Differences in basal activity state (basal arousal) may be important in determining both this response variability and the pattern of drug influence on behavioral and physiological responses to natural arousing stimuli and other drugs. OBJECTIVES To evaluate the changes in brain, muscle, and skin temperatures, and in locomotion induced in rats by several arousing stimuli and intravenous (i.v.) cocaine; and to assess how these responses are modulated by diazepam at a relatively low dose (1 mg/kg, i.p.). MATERIALS AND METHODS Male rats were implanted with thermal probes in the nucleus accumbens (NAcc), temporal muscle, and subcutaneously, and equipped with a chronic i.v. catheter. They were exposed to 1-min tail-pinch, 1-min social interaction with another male and cocaine (1 mg/kg, i.v.) after administration of diazepam or saline. RESULTS While the injection of either diazepam or saline resulted in similar locomotor activation and temperature responses, diazepam decreased basal brain and muscle temperatures for about 3 h; the temperature-decreasing effect of diazepam was oppositely related to basal brain temperature (r = -0.51). After diazepam, rats also showed weaker temperature and locomotor responses to both arousing stimuli; the effect was stronger for tail-pinch and for absolute temperature increases than relative changes. Although diazepam significantly decreased cocaine-induced locomotor activation, it had virtually no effects on cocaine-induced temperature responses in all locations. CONCLUSIONS In accordance with the "law of initial values", the temperature-increasing effects of all tested arousing stimuli and temperature-decreasing effect of diazepam depend upon basal brain temperature. The greatest temperature effects are seen with arousing stimuli at low basal arousal (increases) and with diazepam at high basal arousal (decreases). This is a likely explanation for the variability seen with the physiological and behavioral effects of diazepam in animals.
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Affiliation(s)
- Eugene A Kiyatkin
- National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, 5500 Nathan Shock Drive, Baltimore, 21224, MD, USA.
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Trickett EJ. The 1983 Division 27 Award for Distinguished Contributions to Community Psychology and Community Mental Health: Rudolf H. Moos. AMERICAN JOURNAL OF COMMUNITY PSYCHOLOGY 1984; 12:1-5. [PMID: 6369960 DOI: 10.1007/bf00896926] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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Courtright LJ, Kuzell WC. Sparing effect of neurological deficit and trauma on the course of adjuvant arthritis in the rat. Ann Rheum Dis 1965; 24:360-8. [PMID: 5825185 PMCID: PMC1030979 DOI: 10.1136/ard.24.4.360] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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