Examinando por Autor "Durán, Raquel"
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Ítem Aminopeptidase Activities Interact Asymmetrically between Brain, Plasma and Systolic Blood Pressure in Hypertensive Rats Unilaterally Depleted of Dopamine(BIOMEDICINES, 2022) Banegas, Inmaculada; Prieto-Gómez, María Isabel; Segarra, Ana Belén; Vives, Francisco; Martínez-Cañamero, Magdalena; Durán, Raquel; Luna, Juan Dios; Domínguez-Vías, Germán; Ramírez-Sánchez, ManuelBrain dopamine, in relation to the limbic system, is involved in cognition and emotion. These functions are asymmetrically processed. Hypertension not only alters such functions but also their asymmetric brain pattern as well as their bilateral pattern of neurovisceral integration. The central and peripheral renin-angiotensin systems, particularly the aminopeptidases involved in its enzymatic cascade, play an important role in blood pressure control. In the present study, we report how these aminopeptidases from left and right cortico-limbic locations, plasma and systolic blood pressure interact among them in spontaneously hypertensive rats (SHR) unilaterally depleted of dopamine. The study comprises left and right sham and left and right lesioned (dopamine-depleted) rats as research groups. Results revealed important differences in the bilateral behavior comparing sham left versus sham right, lesioned left versus lesioned right, and sham versus lesioned animals. Results also suggest an important role for the asymmetrical functioning of the amygdala in cardiovascular control and an asymmetrical behavior in the interaction between the medial prefrontal cortex, hippocampus and amygdala with plasma, depending on the left or right depletion of dopamine. Compared with previous results of a similar study in Wistar-Kyoto (WKY) normotensive rats, the asymmetrical behaviors differ significantly between both WKY and SHR strains.Ítem Asymmetric interaction of neuropeptidase activities between cortico-limbic structures, plasma and cardiovascular function after unilateral dopamine depletions of the nigrostriatal system(MDPI, 2022-02) Banegas, Inmaculada; Prieto-Gómez, María Isabel; Segarra, Ana Belén; Vives, Francisco; Martínez-Cañamero, Magdalena; Durán, Raquel; Luna, Juan Dios; de-Gasparo, Marc; Domínguez-Vías, Germán; Ramírez-Sánchez, ManuelIn emotional processing, dopamine (DA) plays an essential role, and its deterioration involves important consequences. Under physiological conditions, dopamine exhibits brain asymmetry and coexists with various neuropeptides that can coordinate the processing of brain functions. Brain asymmetry can extend into a broader concept of asymmetric neurovisceral integration, including behavior. The study of the activity of neuropeptide regulatory enzymes (neuropeptidases, NPs) is illustrative. We have observed that the left and right brain areas interact intra- and inter-hemispherically, as well as with peripheral tissues or with physiological parameters such as blood pressure or with behaviors such as turning preference. To obtain data that reflect this integrative behavior, we simultaneously analyzed the impact of left or right brain DA depletion on the activity of various NPs in corticolimbic regions of the left and right hemispheres, such as the medial prefrontal cortex, amygdala and hippocampus, as well as on the plasma activity of the same aminopeptidase activities (APs) and on systolic blood pressure (SBP). Intra- and inter-hemispheric interactions as well as the interactions of NPs from the left or right hemispheres were analyzed with the same plasma APs and the SBP obtained from sham and from left or right lesioned rats. The results demonstrate a complex profile depending on the hemisphere considered. They definitively confirm an asymmetric neurovisceral integration and reveal a higher level of inter-hemispheric corticolimbic interactions including with SBP after left dopamine depletion.Ítem Asymmetric Pattern of Correlations of Leucine Aminopeptidase Activity between Left or Right Frontal Cortex versus Diverse Left or Right Regions of Rat Brains(MDPI, 2023-07) Ramírez-Sánchez, Manuel; Prieto-Gómez, María Isabel; Segarra, Ana Belén; Banegas, Inmaculada; Martínez-Cañamero, Magdalena; Domínguez-Vías, Germán; Durán, Raquel; Vives, FranciscoPrevious studies demonstrated an asymmetry of left predominance for mean values of soluble leucine aminopeptidase (LeuAP) activity in the frontal cortex (FC) and hypothalamus of adult male rats, fluorimetrically analyzed by the hydrolysis of Leu-β-naphthylamide as a substrate. No asymmetries were observed in nine other left (L) and right (R) regions obtained from rostro-caudally sectioned coronal slices. Neither had inter-hemispheric differences observed for lactate dehydrogenase (LDH), analyzed simultaneously in the same brain regions (L and R) of the same animals. However, the level of intra-hemispheric or inter-hemispheric correlation of LeuAP or LDH between such brain regions has not been analyzed. In order to obtain additional suggestions on the functional heterogeneity between regions of LeuAP and LDH, in the present investigation, the level of intra-hemispheric and inter-hemispheric correlations of the frontal cortex with the rest of the regions studied is described: (A) between the left frontal cortex (LFC) and the rest of the left regions; (B) between the right frontal cortex (RFC) and the rest of the right regions; (C) between the left frontal cortex and all of the right regions; and (D) between the right frontal cortex and all of the left regions. All of the correlations obtained were positive. The intra-hemispheric analysis showed a greater heterogeneity of values in the correlations observed between RFC and the rest of the right regions than between LFC and the rest of the left regions. Greater heterogeneity is observed when comparing RFC correlations with left regions than when comparing LFC correlations with right regions. In conclusion, the greatest heterogeneity (suggesting a greater functional variability) was observed in the right intra-hemispheric analysis and in the inter-hemispheric analysis between the RFC and the left hemisphere. The results for LDH showed a great homogeneity between regions both in the intra- and inter-hemispheric studies.Ítem Bilateral Correlational Behavior of Pyroglutamate Aminopeptidase I Activity in Rat Photoneuroendocrine Locations During a Standard 12:12 h Light-Dark Cycle(MDPI, 2024-11) Ramírez-Sánchez, Manuel; Prieto-Gómez, María Isabel; Segarra, Ana Belén; Banegas, Inmaculada; Martínez-Cañamero, Magdalena; Domínguez-Vías, Germán; Durán, Raquel; Vives, FranciscoWe previously described the circadian variation and bilateral distribution of pyroglutamate aminopeptidase I (pGluPI) activity levels in photoneuroendocrine locations of adult male rats during a standard 12:12 h light-dark cycle. However, the correlational analysis between such locations has not yet been studied. This may provide new data about the unilateral and bilateral functional interaction between photoneuroendocrine locations under light and dark conditions. We analyzed the correlations between locations of a photoneuroendocrine circuit consisting of retina, anterior hypothalamus, superior cervical ganglion, and pineal gland, as well as other related photoneuroendocrine locations: posterior hypothalamus, anterior pituitary, posterior pituitary, occipital cortex, and serum. In particular, we analyzed the correlations between the left retina or the right retina versus the rest of the locations, as well as the correlations between the left and right sides of paired structures at the different time points selected from 12 h light and 12 h dark periods. Also, the profiles of correlational results were compared with the corresponding mean levels. The results demonstrate the complexity of asymmetrical brain behavior. The correlation profile did not always parallel the profile observed with the mean activity values. The diurnal behavior of correlations with the left or right retina differed from one location to another. Likewise, the diurnal variation of correlations between the left and right sides of the paired structures differed between them. Particularly, while most correlations between the left versus right sides of paired structures showed positive values, that of the posterior hypothalamus showed a negative value at 13 h of light period. In addition, except the posterior hypothalamus, most paired locations only correlated significantly with right retina at 07 h of the light period. The results demonstrate the dynamic complexity of brain asymmetry, which represents a challenge for understanding its functional meaning.Ítem Correlational Study of Aminopeptidase Activities between Left or Right Frontal Cortex versus the Hypothalamus, Pituitary, Adrenal Axis of Spontaneously Hypertensive Rats Treated with Hypotensive or Hypertensive Agents.(MDPI, 2023-11-06) Prieto-Gómez, María Isabel; Segarra, Ana Belén; Banegas, Inmaculada; Martínez-Cañamero, Magdalena; Durán, Raquel; Vives, Francisco; Domínguez-Vías, Germán; Ramírez-Sánchez, ManuelIt has been suggested that the neuro-visceral integration works asymmetrically and that this asymmetry is dynamic and modifiable by physio-pathological influences. Aminopeptidases of the renin-angiotensin system (angiotensinases) have been shown to be modifiable under such conditions. This article analyzes the interactions of these angiotensinases between the left or right frontal cortex (FC) and the same enzymes in the hypothalamus (HT), pituitary (PT), adrenal (AD) axis (HPA) in control spontaneously hypertensive rats (SHR), in SHR treated with a hypotensive agent in the form of captopril (an angiotensin-converting enzyme inhibitor), and in SHR treated with a hypertensive agent in the form of the L-Arginine hypertensive analogue L-NG-Nitroarginine Methyl Ester (L-NAME). In the control SHR, there were significant negative correlations between the right FC with HPA and positive correlations between the left FC and HPA. In the captopril group, the predominance of negative correlations between the right FC and HPA and positive correlations between the HPA and left FC was maintained. In the L-NAME group, a radical change in all types of interactions was observed; particularly, there was an inversion in the predominance of negative correlations between the HPA and left FC. These results indicated a better balance of neuro-visceral interactions after captopril treatment and an increase in these interactions in the hypertensive animals, especially in those treated with L-NAME.Ítem Stress influences brain enkephalinase, oxytocinase and angiotensinase activities: a new hypothesis.(Karger, 2009-05-20) Hernández, Joaquín; Segarra, Ana Belén; Ramírez-Sánchez, Manuel; Banegas, Inmaculada; de-Gasparo, Marc; Alba, Francisco; Vives, Francisco; Durán, Raquel; Prieto-Gómez, María IsabelBrain enkephalin and oxytocin are anxiolytic agents involved in the response mechanism to stress. Degrading enzymes such as enkephalinase and oxytocinase could also be associated with this response. The effect of acute immobilization stress on enkephalinase and oxytocinase activities was determined in the soluble and membrane fractions of the medial prefrontal cortex, hippocampus and amygdala using alanyl- and leucyl-beta-naphthylamide as substrates, the latter in the presence and absence of 20 mM L-methionine. No change in aminopeptidase activities was observed in the prefrontal cortex of stressed rats. In contrast, enkephalinase activity decreased in the soluble fraction of the hippocampus but increased in the membrane fraction. In the amygdala, soluble oxytocinase and membrane enkephalinase activities decreased in stressed animals. These results show that acute immobilization stress affects differentially enkephalinase and oxytocinase activities depending on the fraction and brain region analyzed. A reduction in the activity of soluble enkephalinase in the hippocampus and soluble oxytocinase as well as membrane enkephalinase in the amygdala may suggest higher availability/longer action of enkephalin and oxytocin at these locations. This may explain the relative importance of these enzymatic activities in the anxiolytic properties proposed for enkephalins and oxytocin in the hippocampus and amygdala during stress conditions. This interpretation is not applicable to membrane enkephalinase activity in the hippocampus. However, alanyl-beta-naphthylamide hydrolyzing activity not only measures enkephalinase activity, it also reflects the angiotensinase-induced metabolism of angiotensin III to angiotensin IV. Therefore, our results may also mirror an increase in the formation of Ang IV in hippocampus and a decrease in the amygdala in acute stress. In conclusion, aminopeptidase activities in the hippocampus and amygdala may affect enkephalin, oxytocin and angiotensin III metabolism during acute immobilization stress and therefore be involved in the anxiolytic response.