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11.
Gabriel López-Ramírez Rodolfo Sánchez-Zavaleta Arturo Ávalos-Fuentes Juan José Sierra Francisco Paz-Bermúdez Gerardo Leyva-Gómez José Segovia Vila Hernán Cortés Benjamín Florán 《Synapse (New York, N.Y.)》2020,74(3):e22139
CB2 receptors (CB2R) are expressed in midbrain neurons. To evidence the control of dopamine release in dorsal striatum by CB2R, we performed experiments of [3H]-dopamine release in dorsal striatal slices. We found a paradoxical increase in K+-induced [3H]-dopamine release by CB2R activation with GW 833972A and JWH 133 two selective agonist. To understand the mechanism involved, we tested for a role of the D2 autoreceptor in this effect; because in pallidal structures, the inhibitory effect of CB1 receptors (CB1R) on GABA release is switched to a stimulatory effect by D2 receptors (D2R). We found that the blockade of D2 autoreceptors with sulpiride prevented the stimulatory effect of CB2R activation; in fact, under this condition, CB2R decreased dopamine release, indicating the role of the D2 autoreceptor in the paradoxical increase. We also found that the effect occurs in nigrostriatal terminals, since lesions with 6-OH dopamine in the middle forebrain bundle prevented CB2R effects on release. In addition, D2–CB2R interaction promoted cAMP accumulation, and the increase in [3H]-dopamine release was prevented by PKA blockade. D2–CB2R coprecipitation and proximity ligation assay studies indicated a close interaction of receptors that could participate in the observed effects. Finally, intrastriatal injection of CB2R agonist induced contralateral turning in amphetamine-treated rats, which was prevented by sulpiride, indicating the role of the interaction in motor behavior. Thus, these data indicate that the D2 autoreceptor switches, from inhibitory to stimulatory, the CB2R effects on dopamine release, involving the cAMP → PKA pathway in nigrostriatal terminals. 相似文献
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Daniela Denisse Castro-Enríquez Francisco Rodríguez-Félix Benjamín Ramírez-Wong Patricia Isabel Torres-Chávez María Mónica Castillo-Ortega Dora Evelia Rodríguez-Félix Lorena Armenta-Villegas Ana Irene Ledesma-Osuna 《Materials》2012,5(12):2903-2916
Homogeneous and thin porous membranes composed of oriented fibers were obtained from wheat gluten (WG) using the electrospinning technique. SEM micrographs showed an asymmetric structure and some porosity, which, in addition to a small thickness of 40 μm, are desirable characteristics for the membranes’ potential application in release systems. The membranes were loaded with urea to obtain pastilles. FT-IR and DSC studies confirmed the existence of interactions via hydrogen bonding between urea and WG proteins. The pastilles were studied as prolonged-released systems of urea in water. The release of urea during the first 10 min was very fast; then, the rate of release decreased as it reached equilibrium at 300 min, with a total of ≈98% urea released. TGA analysis showed that the release system obtained is thermally stable up to a temperature of 117 °C. It was concluded that a prolonged-release system of urea could be satisfactorily produced using WG fibers obtained by electrospinning for potential application in agricultural crops. 相似文献
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Rijo P Gaspar-Marques C Simões MF Duarte A Del Carmen Apreda-Rojas M Cano FH Rodríguez B 《Journal of natural products》2002,65(10):1387-1390
Three new diterpenoids, a neoclerodane and two labdane derivatives, have been isolated from an acetone extract of Plectranthus ornatus. The structures of these compounds (plectrornatins A-C, 1-3, respectively) were established mainly by spectroscopic means, particularly by 1D and 2D NMR studies and, in the case of the neoclerodane 1, by an X-ray diffraction analysis. Compounds 1 and 3 showed moderate antimicrobial activity against five Candida species and selected Gram negative and Gram positive bacteria strains. 相似文献
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Arginine-vasopressin (VP), also known as the antidiuretic hormone, is essential for water homeostasis. Its synthesis and liberation depends on regulation of osmotic, hypovolemic, hormonal, and nonosmotic stimuli. It has been demonstrated that it is key for maintenance of cardiovascular homeostasis through vasomotor regulation, the determinant of systemic vascular resistance and mean arterial pressure, a process acting through V1 receptors. Shock state with refractory vasodilation seen in sepsis, systemic inflammatory response, hypovolemia, cardiac arrest, polytrauma, etc., is characterized by an initial phase of liberation and increased levels of VP followed by a second phase characterized by inappropriately low levels of this hormone that are associated with refractoriness to management with volume, inotropics, and vasopressors. It has been demonstrated in clinical and experimental studies that exogenous VP treatment under this condition increases systemic vascular resistance, perfusion pressure, and oxygen supply to peripheral tissues, which makes it possible to decrease and to suspend vasopressors and also to increase survival. 相似文献
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Information concerning the anatomy of the physiological foramen is limited. The aim of this study was to investigate the distance between the physiological and anatomical apex, accessory foramina frequency, and the shape and diameter of the physiological foramen in maxillary and mandibular molars. The apical anatomy of 523 maxillary and 574 mandibular molars from an Egyptian population was investigated by means of a computer-aided stereomicroscope (40 x magnification). The following results were obtained: 相似文献
20.
Chondroblastoma is an uncommon primary bone tumor, mainly found in the epiphyses of long bones. We describe a 9-year-old girl who presented with a chondroblastoma as a subungual mass in the fifth toe. Radiographs showed an expansive, calcified tumor of the distal phalanx. Histologic examination after excision revealed chondroid differentiation, active mitosis, multinucleated giant cells, calcification, and necrosis. There was no recurrence of the lesion after surgical excision. The purpose of this report is to document this unusual event that occurred in such a short bone as the distal phalanx of the fifth toe, mimicking a dermatologic entity. 相似文献