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Wright JW, Harding JW. Regulatory role of brain angiotensins in the control of physiological and behavioral responses. ACTA ACUST UNITED AC 1992; 17:227-62. [PMID: 1361394 DOI: 10.1016/0165-0173(92)90018-h] [Citation(s) in RCA: 232] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Considerable evidence now indicates that a separate and distinct renin-angiotensin system (RAS) is present within the brain. The necessary precursors and enzymes required for the formation and degradation of the biologically active forms of angiotensins have been identified in brain tissues as have angiotensin binding sites. Although this brain RAS appears to be regulated independently from the peripheral RAS, circulating angiotensins do exert a portion of their actions via stimulation of brain angiotensin receptors located in circumventricular organs. These circumventricular organs are located in the proximity of brain ventricles, are richly vascularized and possess a reduced blood-brain barrier thus permitting accessibility by peptides. In this way the brain RAS interacts with other neurotransmitter and neuromodulator systems and contributes to the regulation of blood pressure, body fluid homeostasis, cyclicity of reproductive hormones and sexual behavior, and perhaps plays a role in other functions such as memory acquisition and recall, sensory acuity including pain perception and exploratory behavior. An overactive brain RAS has been identified as one of the factors contributing to the pathogenesis and maintenance of hypertension in the spontaneously hypertensive rat (SHR) model of human essential hypertension. Oral treatment with angiotensin-converting enzyme inhibitors, which interfere with the formation of angiotensin II, prevents the development of hypertension in young SHR by acting, at least in part, upon the brain RAS. Delivery of converting enzyme inhibitors or specific angiotensin receptor antagonists into the brain significantly reduces blood pressure in adult SHR. Thus, if the SHR is an appropriate model of human essential hypertension (there is controversy concerning its usefulness), the potential contribution of the brain RAS to this dysfunction must be considered during the development of future antihypertensive compounds.
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Meighan SE, Meighan PC, Choudhury P, Davis CJ, Olson ML, Zornes PA, Wright JW, Harding JW. Effects of extracellular matrix-degrading proteases matrix metalloproteinases 3 and 9 on spatial learning and synaptic plasticity. J Neurochem 2006; 96:1227-41. [PMID: 16464240 DOI: 10.1111/j.1471-4159.2005.03565.x] [Citation(s) in RCA: 218] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Rats learning the Morris water maze exhibit hippocampal changes in synaptic morphology and physiology that manifest as altered synaptic efficacy. Learning requires structural changes in the synapse, and multiple cell adhesion molecules appear to participate. The activity of these cell adhesion molecules is, in large part, dependent on their interaction with the extracellular matrix (ECM). Given that matrix metalloproteinases (MMPs) are responsible for transient alterations in the ECM, we predicted that MMP function is critical for hippocampal-dependent learning. In support of this, it was observed that hippocampal MMP-3 and -9 increased transiently during water maze acquisition as assessed by western blotting and mRNA analysis. The ability of the NMDA receptor channel blocker MK801 to attenuate these changes indicated that the transient MMP changes were in large part dependent upon NMDA receptor activation. Furthermore, inhibition of MMP activity with MMP-3 and -9 antisense oligonucleotides and/or MMP inhibitor FN-439 altered long-term potentiation and prevented acquisition in the Morris water maze. The learning-dependent MMP alterations were shown to modify the stability of the actin-binding protein cortactin, which plays an essential role in regulating the dendritic cytoskeleton and synaptic efficiency. Together these results indicate that changes in MMP function are critical to synaptic plasticity and hippocampal-dependent learning.
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Research Support, U.S. Gov't, Non-P.H.S. |
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Wright JW, Harding JW. Brain angiotensin receptor subtypes in the control of physiological and behavioral responses. Neurosci Biobehav Rev 1994; 18:21-53. [PMID: 8170622 DOI: 10.1016/0149-7634(94)90034-5] [Citation(s) in RCA: 209] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This review summarizes emerging evidence that supports the notion of a separate brain renin-angiotensin system (RAS) complete with the necessary precursors and enzymes for the formation and degradation of biologically active forms of angiotensins, and several binding subtypes that may mediate their diverse functions. Of these subtypes the most is known about the AT1 site which preferentially binds angiotensin II (AII) and angiotensin III (AIII). The AT1 site appears to mediate the classic angiotensin responses concerned with body water balance and the maintenance of blood pressure. Less is known about the AT2 site which also binds AII and AIII and may play a role in vascular growth. Recently, an AT3 site was discovered in cultured neoblastoma cells, and an AT4 site which preferentially binds AII(3-8), a fragment of AII now referred to as angiotensin IV (AIV). The AT4 site has been implicated in memory acquisition and retrieval, and the regulation of blood flow. In addition to the more well-studied functions of the brain RAS, we review additional less well investigated responses including regulation of cellular function, the modulation of sensory and motor systems, long term potentiation, and stress related mechanisms. Although the receptor subtypes responsible for mediating these physiologies and behaviors have not been definitively identified research efforts are ongoing. We also suggest potential contributions by the RAS to clinically relevant syndromes such as dysfunctions in the regulation of blood flow and ischemia, changes in cognitive affect and memory in clinical depressed and Alzheimer's patients, and angiotensin's contribution to alcohol consumption.
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Ellis J, Krakowka S, Lairmore M, Haines D, Bratanich A, Clark E, Allan G, Konoby C, Hassard L, Meehan B, Martin K, Harding J, Kennedy S, McNeilly F. Reproduction of lesions of postweaning multisystemic wasting syndrome in gnotobiotic piglets. J Vet Diagn Invest 1999; 11:3-14. [PMID: 9925205 DOI: 10.1177/104063879901100101] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Neonatal gnotobiotic piglets were inoculated with tissue homogenates and low- and high-passage cell culture material to determine if the lesions of the newly described porcine postweaning multisystemic wasting syndrome (PMWS) could be reproduced. For this, 17 3-day-old gnotobiotic piglets were inoculated intranasally with pelleted chloroform-treated, filtered extracts from cell cultures, filter-sterilized homogenates of lymphoid tissue from PMWS-affected piglets, or control materials. Piglets were maintained in germ-free isolators for up to 5 weeks after infection prior to euthanasia and collection of samples for analysis. All piglets inoculated with the viral inocula developed lesions typical of PMWS, including generalized lymphadenopathy, hepatitis, nephritis, interstitial pneumonia, myocarditis, and gastritis. Porcine circovirus (PCV), as well as porcine parvovirus (PPV), was detected in tissues by virus reisolation, polymerase chain reaction analysis, or immunohistochemistry. All infected piglets developed moderate to high titers of antibody to PCV and moderate titers to PPV. No lesions, virus, or virus-specific antibodies were detected in sham-inoculated or uninoculated control piglets. These studies demonstrate that the lesions of PMWS can be experimentally reproduced in gnotobiotic piglets using filterable viral agents derived from pigs with PMWS and provide an experimental basis for further investigation into the pathogenesis and control of this emerging infectious disease in swine.
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Wright JW, Harding JW. Important role for angiotensin III and IV in the brain renin-angiotensin system. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1997; 25:96-124. [PMID: 9370053 DOI: 10.1016/s0165-0173(97)00019-2] [Citation(s) in RCA: 189] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Considerable evidence now suggests that the precursors and enzymes necessary for the formation and degradation of biologically active forms of angiotensins are present in brain tissues, accompanied by at least three specific binding sites. It also appears that several forms of angiotensin may serve as signaling agents at these sites. There is accumulating support for the notion that AngII must be converted to AngIII in order to bind at the AT1 and AT2 receptor subtypes, and AngIII must be converted to AngIV in order to activate the AT4 receptor subtype. Further, AngII(1-7) may activate a separate binding site concerned with antidiuresis, however, characterization of this site has not been completed. The AT1 site appears to mediate the classic angiotensin functions concerned with body water balance, maintenance of blood pressure, and cyclicity of reproductive hormones and sexual behaviors. This receptor site also exerts some control over the secretion of pituitary hormones. Less is known about the functional importance of the AT2 site, however, it has been implicated in vascular growth, control of blood flow, and perhaps modulation of NMDA receptors. The AT4 site is heavily distributed in neocortex, hippocampus, cerebellum, and basal ganglia structures, as well as several peripheral tissues. This site appears to mediate memory acquisition and retrieval, the regulation of blood flow, neurite outgrowth, angiogenesis, and kidney function. In addition to the well-studied functions of the brain renin-angiotensin system, additional less well investigated responses are reviewed. These include electrophysiological activation, tachyphylaxis, long term potentiation, learning and memory, and cognitive affect.
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Review |
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Abstract
The brain renin-angiotensin system has been implicated in the central regulation of the cardiovascular system, body water balance, and cyclic regulation of reproductive hormones and behaviors. It also exerts some influence over the secretion of pituitary hormones. This system appears to be complete with the necessary precursors and enzymes for the formation and degradation of biologically active forms of angiotensins and several binding subtypes that are presumed to mediate these and other functions. Much information is now available on the AT1 site which preferentially binds angiotensin II (AngII), but also binds angiotensin III (AngIII), and appears to be responsible for mediating the above described classic angiotensin physiologies and behaviors. Less is known about the functional importance of the AT2 site which also binds AngII but preferentially binds AngIII. This site has been implicated in vascular growth and cerebral blood flow. Recently, an AT4 site has been discovered and characterized that preferentially binds AngII (3-8), a fragment of AngII referred to as angiotensin IV (AngIV). This AT4 site is prominent in cerebral cortex, hippocampus, basal ganglia, cerebellum, and spinal cord, as well as several peripheral tissues including kidney, bladder, heart, spleen, prostate, adrenals, and colon. The AT4 site may mediate memory acquisition and recall and the regulation of blood flow. The function(s) of the AT4 receptor subtype in peripheral tissues is currently unknown, although it does appear to be involved in kidney blood flow.
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Review |
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Stubley-Weatherly L, Harding JW, Wright JW. Effects of discrete kainic acid-induced hippocampal lesions on spatial and contextual learning and memory in rats. Brain Res 1996; 716:29-38. [PMID: 8738217 DOI: 10.1016/0006-8993(95)01589-2] [Citation(s) in RCA: 171] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Substantial information is available concerning the influence of global hippocampal lesions on spatial learning and memory, however the contributions of discrete subregions within the hippocampus to these functions is less well understood. The present investigation utilized kainic acid to bilaterally lesion specific areas of the rat hippocampus. These animals were subsequently tested on a spatial orientation task using a circular water maze, and on an associative/contextual task using passive avoidance conditioning. The results indicate that both the dorsal CA1 and the ventral CA3 subregions play important roles in learning. Specifically, CA1 lesions produced a deficit in the acquisition of the water maze task and a significant memory impairment on the passive avoidance task. CA3 lesions also caused learning deficits in the acquisition of the water maze task, and produced even greater impairments in performance on the passive avoidance task. We conclude that CA1 and CA3 hippocampal subregions each play significant roles in the overall integration of information concerning spatial and associative learning.
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Senapati A, Gray RG, Middleton LJ, Harding J, Hills RK, Armitage NCM, Buckley L, Northover JMA. PROSPER: a randomised comparison of surgical treatments for rectal prolapse. Colorectal Dis 2013; 15:858-68. [PMID: 23461778 DOI: 10.1111/codi.12177] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 02/05/2013] [Indexed: 02/06/2023]
Abstract
AIM Rectal prolapse is a profoundly disabling condition, occurring mainly in elderly and parous women. There is no accepted standard surgical treatment, with previous studies limited in methodological quality and size. PROSPER aimed to address these deficiencies by comparing the relative merits of different procedures. METHOD In a pragmatic, factorial (2 × 2) design trial, patients could be randomised between abdominal and perineal surgery (i), and suture vs resection rectopexy for those receiving an abdominal procedure (ii) or Altemeier's vs Delorme's for those receiving a perineal procedure (iii). Primary outcome measures were recurrence of the prolapse, incontinence, bowel function and quality of life scores (Vaizey, bowel thermometer and EQ-5D) measured up to 3 years. RESULTS Two hundred and ninety-three patients were recruited: 49 were randomised between surgical approaches (i); 78 between abdominal procedures (ii); and 213 between perineal procedures (iii). Recurrence rates were higher than anticipated, but not significantly different in any comparison: Altemeier's vs Delorme's 24/102 (24%) and 31/99 (31%) [hazard ratio (HR) 0.81; 95% CI 0.47, 1.38; P = 0.4]; resection vs suture rectopexy 4/32 (13%) and 9/35 (26%) (HR 0.45; 95% CI 0.14, 1.46; P = 0.2); perineal vs abdominal 5/25 (20%) and 5/19 (26%) (HR 0.83; 95% CI 0.24, 2.86; P = 0.8). Vaizey, bowel thermometer and EQ-5D scores were not significantly different in any of the comparisons. CONCLUSION No significant differences were seen in any of the randomised comparisons, although substantial improvements from baseline in quality of life were noted following all procedures.
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Randomized Controlled Trial |
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Wright JW, Miller-Wing AV, Shaffer MJ, Higginson C, Wright DE, Hanesworth JM, Harding JW. Angiotensin II(3-8) (ANG IV) hippocampal binding: potential role in the facilitation of memory. Brain Res Bull 1993; 32:497-502. [PMID: 8221142 DOI: 10.1016/0361-9230(93)90297-o] [Citation(s) in RCA: 158] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The present research characterizes a newly discovered ANG II(3-8) (ANG IV) binding site localized in structures associated with memory function (hippocampus, neocortex, cerebellum), as well as other brain stem structures (thalamus, inferior olivary nucleus). This site is not the AT1 or AT2 site that binds angiotensins II (ANG II) and III (ANG III) nor does it bind the nonpeptide AT1 or AT2 receptor antagonists DuP753 and PD123177, respectively. The intracerebroventricular (ICV) infusion of ANG IV was ineffective at inducing drinking in rats as compared with equivalent doses of ANG II and III. Although not as effective as ANG II or ANG III, ICV infusion of ANG IV did provoke a pressor response at the highest dose (100 pmol/min), which appeared to be mediated by ANG II (AT1)-type receptors and not the specific AIV binding site described here. By contrast, the ICV infusion of ANG IV resulted in greater effects upon retention and retrieval of a passive avoidance task as compared with ANG II. Specifically, ANG II was not different from the ICV infusion of artificial cerebrospinal fluid, while ANG IV improved retention and retrieval of this task.
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Lê AD, Corrigall WA, Harding JW, Juzytsch W, Li TK. Involvement of nicotinic receptors in alcohol self-administration. Alcohol Clin Exp Res 2000; 24:155-63. [PMID: 10698366 DOI: 10.1111/j.1530-0277.2000.tb04585.x] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Alcohol and nicotine, in the form of tobacco, are commonly co-abused. Nicotinic receptors also have been implicated in alcohol action. We designed the present study to examine the possible involvement of nicotinic receptors in alcohol self-administration. METHODS AND RESULTS Pretreatment with lower doses (0.1-0.4 mg/kg) of nicotine, administered acutely or chronically, did not affect alcohol consumption, whereas a higher dose (0.8 mg/kg) initially suppressed alcohol consumption but stimulated alcohol consumption on repeated treatment. We observed the same pattern of nicotine effects on alcohol self-administration using an operant procedure. A dose of 0.8 mg/kg of nicotine initially suppressed operant responding for alcohol. Such suppression of alcohol self-administration was more pronounced during the first 20 min of the 60 min operant session. Responding for alcohol in the nicotine treated group, however, was significantly increased above the saline treated group by the 5th day of treatment. Mecamylamine, a noncompetitive nicotinic receptor antagonist, reduced alcohol consumption, whereas dihydro-beta-erythroidine (DHbetaE), a competitive nicotinic receptor antagonist, did not modify alcohol consumption. CONCLUSIONS The stimulation of alcohol intake induced by nicotine treatment and the suppression of alcohol intake induced by mecamylamine provide evidence for the involvement of nicotinic receptors in alcohol consumption and/or self-administration. The failure of DHbetaE to reduce alcohol consumption, however, suggests that ethanol-nicotine interaction is mediated by other nicotinic receptor subtypes rather than alpha4beta2 receptor subtype, or that mecamylamine acts through a nonnicotinic mechanism.
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Wright JW, Harding JW. The brain renin–angiotensin system: a diversity of functions and implications for CNS diseases. Pflugers Arch 2012; 465:133-51. [DOI: 10.1007/s00424-012-1102-2] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 03/20/2012] [Accepted: 03/30/2012] [Indexed: 12/14/2022]
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Harding J, Graziadei PP, Monti Graziadei GA, Margolis FL. Denervation in the primary olfactory pathway of mice. IV. Biochemical and morphological evidence for neuronal replacement following nerve section. Brain Res 1977; 132:11-28. [PMID: 890470 DOI: 10.1016/0006-8993(77)90703-x] [Citation(s) in RCA: 151] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Unilateral olfactory nerve section was performed in the mouse. Three biochemical markers of the olfactory chemoreceptor neurons: carnosine, carnosine synthetase activity and the olfactory marker protein, were measured in the olfactory bulb and epithelium. Parallel observations were made by light microscopy as well as at the ultrastructural level. The specific biochemical markers decrease rapidly in both bulb and epithelium and reach a minimum by the end of the first week after surgery. They then slowly return to 80% of control values by one month. Carnosinase activity in epithelium was essentially unaffected. These biochemical observations coincide temporally with the onset of degenerative changes seen morphologically, in both the bulb and epithelium. The degenerative changes persist for up to two weeks in the bulb and for about one week in the epithelium. At this time basal cell division and differentiation begins in the epithelium with subsequent regrowth of olfactory axons into the glomerular layer of the olfactory bulb with ther reappearance of olfactory axon terminals. The temporal coincidence of these biochemical and morphological observations suggests they are manifestations of the same process, and is consistent with the idea that the olfactory chemoreceptor neurons are perhaps unique in being able to be replaced from undifferentiated stem cells.
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Monti-Graziadei GA, Margolis FL, Harding JW, Graziadei PP. Immunocytochemistry of the olfactory marker protein. J Histochem Cytochem 1977; 25:1311-6. [PMID: 336785 DOI: 10.1177/25.12.336785] [Citation(s) in RCA: 151] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The olfactory marker protein has been localized, by means of immunohistochemical techniques in the primary olfactory neurons of mice. The olfactory marker protein is not present in the staminal cells of the olfactory neuroepithelium, and the protein may be regarded as indicative of the functional stage of the neurons. Our data indicate that the olfactory marker protein is present in the synaptic terminals of the olfactory neurons at the level of the olfactory bulb glomeruli. The postsynaptic profiles of both mitral and periglomerular cells are negative.
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Wright JW, Harding JW. Brain renin-angiotensin—A new look at an old system. Prog Neurobiol 2011; 95:49-67. [DOI: 10.1016/j.pneurobio.2011.07.001] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 06/27/2011] [Accepted: 07/03/2011] [Indexed: 12/15/2022]
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de Gasparo M, Husain A, Alexander W, Catt KJ, Chiu AT, Drew M, Goodfriend T, Harding JW, Inagami T, Timmermans PB. Proposed update of angiotensin receptor nomenclature. Hypertension 1995; 25:924-7. [PMID: 7737728 DOI: 10.1161/01.hyp.25.5.924] [Citation(s) in RCA: 142] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Harding JW, Getchell TV, Margolis FL. Denervation of the primary olfactory pathway in mice. V. Long-term effect of intranasal ZnSO4 irrigation on behavior, biochemistry and morphology. Brain Res 1978; 140:271-85. [PMID: 626892 DOI: 10.1016/0006-8993(78)90460-2] [Citation(s) in RCA: 132] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Intranasal irrigation of mice with 0.17 M ZnSO4 solution results in the immediate and total loss of the ability to find a buried food pellet. This anosmia persists for 6 weeks in at least 80% of the treated mice and for 4 months in half of the animals. This marked behavioral effect is matched by a long-term reduction of the levels of carnosine synthesis and transport in the primary olfactory pathway. These biochemical parameters are virtually undetectable at two weeks after treatment and even at one year after treatment do not exceed 5-10% of average control values. Light microscopic observations of tissues of the primary olfactory pathway at various times after treatment are consistent with these observations and indicate a substantial destruction of the olfactory epithelium with subsequent atrophy of the olfactory bulb. At very long intervals after treatment, some receptor regeneration is apparent with accompanying reinnervation of the olfactory bulb. Estimates from microscopy and biochemistry suggest that much less than 10% of the normal complement of functioning receptor cells is adequate to give apparently normal food-finding behavior.
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Wright JW, Harding JW. Brain angiotensin receptor subtypes AT1, AT2, and AT4 and their functions. REGULATORY PEPTIDES 1995; 59:269-95. [PMID: 8577933 DOI: 10.1016/0167-0115(95)00084-o] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Review |
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128 |
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Ellis JA, Bratanich A, Clark EG, Allan G, Meehan B, Haines DM, Harding J, West KH, Krakowka S, Konoby C, Hassard L, Martin K, McNeilly F. Coinfection by porcine circoviruses and porcine parvovirus in pigs with naturally acquired postweaning multisystemic wasting syndrome. J Vet Diagn Invest 2000; 12:21-7. [PMID: 10690771 DOI: 10.1177/104063870001200104] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Postweaning multisystemic wasting syndrome (PMWS) is an emerging disease in swine. Recently, the disease has been reproduced with inocula containing a newly described porcine circovirus (PCV), designated PCV 2, and porcine parvovirus (PPV). In order to determine if these viruses interact in naturally acquired PMWS, affected tissues from field cases were examined by immunohistochemistry (IHC) and polymerase chain reaction (PCR) for PCV 2 and PPV, as well as by PCR for the other recognized porcine circovirus, PCV 1. Porcine circovirus 2 was detected by PCR or IHC in affected fixed or frozen tissues from 69 of 69 cases of PMWS collected over 3 years from 25 farms. Porcine parvovirus was detected in 12 of the same cases, and PCV 1 was detected in 9 of 69; however, an apparent decrease was found in the sensitivity of the PCRs used to detect the latter 2 viruses when fixed tissue from the same cases were compared with the use of frozen tissues. Porcine circovirus 2 was not detected by PCR in affected tissues from 16 age-matched pigs that had Streptococcus suis-associated disease. Electron microscopic examination of plasma pooled from 15 pigs with PMWS revealed the presence of PCV and PPV, whereas these viruses were not observed in pooled plasma from 5 age-matched clinically normal pigs. These results confirm and extend previous findings documenting a consistent association of PCV 2 with PMWS. As well, infection by PPV or PCV 1 or both may be an important cofactor in the pathogenesis of some, but apparently not all, cases of PMWS.
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Harding JW, Cook VI, Miller-Wing AV, Hanesworth JM, Sardinia MF, Hall KL, Stobb JW, Swanson GN, Coleman JK, Wright JW. Identification of an AII(3-8) [AIV] binding site in guinea pig hippocampus. Brain Res 1992; 583:340-3. [PMID: 1504842 DOI: 10.1016/s0006-8993(10)80047-2] [Citation(s) in RCA: 121] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A unique angiotensin binding site specific for the hexapeptide, AII(3-8), has been identified in guinea pig hippocampus. This binding site, which is present in the pyramidal cell layer of CA1, CA2, CA3 of the hippocampus and dentate gyrus, binds AII(3-8) with high affinity (KD = 1.29 +/- 0.18 nM) in a saturable manner (Bmax = 449 +/- 62 fmol/mg protein). The N-terminal structure of the binding ligand is paramount in determining the binding affinity. The C-terminal requirements seem less stringent as evidenced by the binding affinity of AII(3-7) (KD = 20.9 +/- 2.1 nM). Neither AII, AIII,Sar1, Ile8-AII, Dup 753 nor CGP42112A appear to bind, indicating that this binding site is neither the AT1 nor AT2 sites described for AII/AIII. Autoradiographic analysis of hippocampus binding confirms the inability of Sar1,Ile8-AII to compete for [125I]AII(3-8) binding. Conversely AII(3-8) was unable to displace [125I]Sar1,Ile8-AII binding.
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Wright JW, Harding JW. The brain angiotensin system and extracellular matrix molecules in neural plasticity, learning, and memory. Prog Neurobiol 2004; 72:263-93. [PMID: 15142685 DOI: 10.1016/j.pneurobio.2004.03.003] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2003] [Accepted: 03/18/2004] [Indexed: 01/25/2023]
Abstract
The brain renin-angiotensin system (RAS) has long been known to regulate several classic physiologies including blood pressure, sodium and water balance, cyclicity of reproductive hormones and sexual behaviors, and pituitary gland hormones. These physiologies are thought to be under the control of the angiotensin II (AngII)/AT1 receptor subtype system. The AT2 receptor subtype is expressed during fetal development and is less abundant in the adult. This receptor appears to oppose growth responses facilitated by the AT1 receptor, as well as growth factor receptors. Recent evidence points to an important contribution by the brain RAS to non-classic physiologies mediated by the newly discovered angiotensin IV (AngIV)/AT4 receptor subtype system. These physiologies include the regulation of blood flow, modulation of exploratory behavior, and a facilitory role in learning and memory acquisition. This system appears to interact with brain matrix metalloproteinases in order to modify extracellular matrix molecules thus permitting the synaptic remodeling critical to the neural plasticity presumed to underlie memory consolidation, reconsolidation, and retrieval. There is support for an inhibitory influence by AngII activation of the AT1 subtype, and a facilitory role by AngIV activation of the AT4 subtype, on neuronal firing rate, long-term potentiation, associative and spatial learning. The discovery of the AT4 receptor subtype, and its facilitory influence upon learning and memory, suggest an important role for the brain RAS in normal cognitive processing and perhaps in the treatment of dysfunctional memory disease states.
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Review |
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120 |
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Cooper LJ, Wacker DP, Thursby D, Plagmann LA, Harding J, Millard T, Derby M. Analysis of the effects of task preferences, task demands, and adult attention on child behavior in outpatient and classroom settings. J Appl Behav Anal 1992; 25:823-40. [PMID: 1478905 PMCID: PMC1279767 DOI: 10.1901/jaba.1992.25-823] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two studies were conducted with children who displayed behavior problems to evaluate the effects of task preference, task demands, and adult attention on child behavior. In Study 1, we conducted brief functional analyses in an outpatient clinic to identify variables that facilitated appropriate behavior. For 8 of 10 children, distinct patterns of performance occurred; 3 children displayed improved behavior with changes in task demands, 1 child displayed improved behavior with a preferred task, and 4 children displayed improved behavior with changes in adult attention. In most cases, the children's parents carried out the assessments with adequate procedural integrity. In Study 2, we applied similar assessment methods to a classroom setting over an extended period of time. We identified independent variables controlling appropriate, on-task, and academic behavior for 2 children on two tasks, with slightly different treatment procedures across tasks for both children. In addition, the results of brief functional analyses for both children corresponded to the extended classroom assessments.
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research-article |
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Abstract
The distribution of specific angiotensin II (AII) binding capacity of several brain regions, pituitary, and adrenals was determined in 6 rodent species namely rats, mice, hamsters, kangaroo rats, gerbils and degus. Rats and mice had similar distributions with the highest levels of binding observed in the area postrema, septum and superior colliculi. Low levels were seen in the cortex, cerebellum, striatum and hippocampus. Other areas had intermediate levels. The distribution of AII binding in gerbils and degus was strikingly different from rats and mice. In these species, little or no binding could be detected in the brain. Additionally, the level of binding in degu adrenals was extremely low when compared to the binding observed in the adrenals of the other species. The distribution of AII binding sites in hamsters and kangaroo rats, although similar in some ways to rats and mice, had several major differences. Both had much higher levels of specific binding in cerebellum, striatum, and the hippocampus areas which had low levels of AII binding in rats an mice. Hamsters were the only species to exhibit significant specific binding in the cortex. The kangaroo rats had an unusual distribution of receptors with an apparent lack of specific binding in midbrain and area postrema.
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Comparative Study |
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108 |
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Tseng AH, Harding JW, Craft RM. Pharmacokinetic factors in sex differences in Δ9-tetrahydrocannabinol-induced behavioral effects in rats. Behav Brain Res 2004; 154:77-83. [PMID: 15302113 DOI: 10.1016/j.bbr.2004.01.029] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2003] [Revised: 12/01/2003] [Accepted: 01/25/2004] [Indexed: 11/19/2022]
Abstract
Cannabinoids have been shown to produce greater behavioral effects in female than in male rats. Sex differences in the metabolism of Delta(9)-tetrahydrocannabinol (Delta(9)-THC) have also been demonstrated in one study. The goal of this study was to determine if sex differences in Delta(9)-THC disposition or metabolism could explain sex differences in Delta(9)-THC-induced behavioral effects. [(3)H]-Delta(9)-THC was administered intraperitoneally (i.p.) to rats and the presence of [(3)H]-Delta(9)-THC and metabolites in serum and brain tissue were compared at multiple times post-injection in male versus female rats. Serum levels of Delta(9)-THC and its metabolites were similar in males and females. In brain tissue, [(3)H]-Delta(9)-THC levels also were similar in males and females. In contrast, levels of Delta(9)-THC metabolites in brain tissue, including 11-hydroxy-Delta(9)-THC, the major active metabolite, were higher in females than in males. To further investigate if greater production of active metabolites by females explained the greater Delta(9)-THC-induced behavioral effects observed in females, i.p. Delta(9)-THC-induced antinociception (50 degrees C warm water tail withdrawal assay) and catalepsy (bar test) were compared in male and female rats following pretreatment with saline or SKF525A, a cytochrome P450 inhibitor. SKF525A did not affect basal responding in the tail withdrawal assay or bar test in either sex. SKF525A significantly attenuated Delta(9)-THC-induced antinociception only in females. A similar sex difference was observed in the effects of SKF525A on Delta(9)-THC-induced catalepsy. These results suggest that the greater levels of active Delta(9)-THC metabolites produced by females contribute to greater behavioral effects of Delta(9)-THC in female compared to male rats.
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Lincoln NB, Dent A, Harding J, Weyman N, Nicholl C, Blumhardt LD, Playford ED. Evaluation of cognitive assessment and cognitive intervention for people with multiple sclerosis. J Neurol Neurosurg Psychiatry 2002; 72:93-8. [PMID: 11784832 PMCID: PMC1737698 DOI: 10.1136/jnnp.72.1.93] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES Cognitive problems in multiple sclerosis are common but any possible benefits of treatment remain uncertain. The aim of the study was to evaluate the benefits of providing a psychology service, including cognitive assessment and intervention, to patients with multiple sclerosis. METHOD The study was a single blind randomised controlled trial. A total of 240 patients with clinically definite, laboratory supported, or clinically probable multiple sclerosis were recruited from an multiple sclerosis management clinic and assessed on a brief screening battery. They were randomised into three groups. The control group received no further intervention. The assessment group received a detailed cognitive assessment, the result of which was fed back to staff involved in the patients' care. The treatment group received the same detailed cognitive assessment and a treatment programme designed to help reduce the impact of their cognitive problems. Patients were followed up 4 and 8 months later on the general health questionnaire (GHQ-28), extended activities of daily living scale, SF-36, everyday memory questionnaire, dysexecutive syndrome questionnaire, and memory aids questionnaire. RESULTS The three groups were compared on the outcome measures at 4 and 8 months after recruitment. There were few significant differences between the groups and those that occurred favoured the control group. Overall, the results showed no effect of the interventions on mood, quality of life, subjective cognitive impairment or independence. CONCLUSIONS The study failed to detect any significant effects of cognitive assessment or cognitive intervention in this cohort of people with multiple sclerosis.
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Clinical Trial |
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Harding JW, Felix D. Angiotensin-sensitive neurons in the rat paraventricular nucleus: relative potencies of angiotensin II and angiotensin III. Brain Res 1987; 410:130-4. [PMID: 3580891 DOI: 10.1016/s0006-8993(87)80033-1] [Citation(s) in RCA: 103] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Angiotensin-activated neurons were examined using microiontophoretic methods in the paraventricular nucleus (PNV) of the rat. In all cases angiotensin III (AIII) was more potent than angiotensin II (AII). This greater sensitivity to AIII was manifested by lower thresholds, shorter latencies, and higher spike frequencies/amplitudes of applied current. The superior potency of AIII was further exaggerated in the spontaneously hypertensive rat (SHR) compared with normotensive Wistar Kyoto (WKY) rats. Postactivity for both AII and AIII was greatly prolonged in SHR. This appeared specific since no prolongation in acetylcholine postactivity was seen in SHR. These data support the notion that AIII may be the centrally active form of angiotensin and are consistent with an obligatory conversion of AII to AIII prior to activation. The selective enhancement of postactivity observed in SHR following angiotensin application suggests a possible defect in signal termination.
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Comparative Study |
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103 |