Synthesis and biological evaluation of novel pazopanib derivatives as antitumor agents

A series of novel pazopanib derivatives, 7a–m, were designed and synthesized by modification of terminal benzene and indazole rings in pazopanib. The structures of all the synthesized compounds were confirmed by ¹H NMR and MS. Their inhibitory activity against VEGFR-2, PDGFR-α and c-kit tyrosine kinases were evaluated. All the compounds exhibited definite kinase inhibition, in which compound 7l was most potent with IC₅₀ values of 12 nM against VEGFR-2. Furthermore, compounds 7c, 7d and 7m demonstrated comparable inhibitory activity against three tyrosine kinases to pazopanib, and compound 7f showed superior inhibitory effects than that of pazopanib.     

Proteomic Analysis of Glycine Receptor β Subunit (GlyRβ)-interacting Proteins: EVIDENCE FOR SYNDAPIN I REGULATING SYNAPTIC GLYCINE RECEPTORS*

Glycine receptors (GlyRs) mediate inhibitory neurotransmission in spinal cord and brainstem. They are clustered at inhibitory postsynapses via a tight interaction of their β subunits (GlyRβ) with the scaffolding protein gephyrin. In an attempt to isolate additional proteins interacting with GlyRβ, we performed pulldown experiments with rat brain extracts using a glutathione S-transferase fusion protein encompassing amino acids 378–455 of the large intracellular loop of GlyRβ as bait. This identified syndapin I (SdpI) as a novel interaction partner of GlyRβ that coimmunoprecipitates with native GlyRs from brainstem extracts. Both SdpI and SdpII bound efficiently to the intracellular loop of GlyRβ in vitro and colocalized with GlyRβ upon coexpression in COS-7 cells. The SdpI-binding site was mapped to a proline-rich sequence of 22 amino acids within the intracellular loop of GlyRβ. Deletion and point mutation analysis disclosed that SdpI binding to GlyRβ is Src homology 3 domain-dependent. In cultured rat spinal cord neurons, SdpI immunoreactivity was found to partially colocalize with marker proteins of inhibitory and excitatory synapses. When SdpI was acutely knocked down in cultured spinal cord neurons by viral miRNA expression, postsynaptic GlyR clusters were significantly reduced in both size and number. Similar changes in GlyR cluster properties were found in spinal cultures from SdpI-deficient mice. Our results are consistent with a role of SdpI in the trafficking and/or cytoskeletal anchoring of synaptic GlyRs.     

Neural mechanisms of auditory information processing by identified interneurones in Orthoptera

Three qualities of sound—the directional, the temporal and the spectral—are important for intraspecific communication in Orthoptera. The neural mechanisms employed by identified interneurones for encoding these sound qualities are illustrated by examples of physiological processes found at different levels of the CNS. Discussed are: (1) the creation of directional information by local interneurones in the thorax, and the use of time-intensity trading in sound location; (2) mechanisms for encoding the temporal parameters of sound by interneurones ascending to the brain; (3) frequency-dependent neural filtering of auditory information by local interneurones.     

Decrease of Clonidine Binding Affinity to α2-Adrenoceptor by ADP-Ribosylation of 41,000-Dalton Proteins in Rat Cerebral Cortical Membranes by Islet-Activating Protein

The IC50 value for inhibition of specific [3H]yohimbine binding to rat cerebral cortical membranes by clonidine was increased, and the Hill coefficient (nH) approached unity in the presence of 150 microM GTP. Pretreatment of membranes with islet-activating protein (IAP) in the presence of NAD caused an increase in IC50 and nH values for clonidine compared with control membranes in the absence of GTP, the addition of which was without effect. Scatchard analysis showed that the Bmax value of the high-affinity component in [3H]clonidine binding was decreased by pretreatment with IAP/NAD. GTP in a concentration range of 0.1 microM-1 mM caused a significant elevation of [3H]yohimbine binding. In IAP/NAD-pretreated membranes, however, [3H]yohimbine binding was no longer affected by GTP, although IAP/NAD significantly (p less than 0.01) increased [3H]yohimbine binding compared to control. IAP ADP-ribosylated 41,000 dalton proteins of cerebral cortical membranes. From these results, it can be suggested that inhibitory guanine nucleotide regulatory protein with Mr 41,000 couples to alpha 2-adrenoceptors to regulate binding affinity of agonists and antagonists in membranes of the rat cerebral cortex.     

Ileo-caecal resection induced pancreatic growth in rats

The effect of ileo-caecal resection on pancreatic growth was studied in rats four weeks after the operation. The results were compared with an identical control group who had undergone laparotomy alone. Pancreatic wet weight in ileo-caecal resectioned rats was 1.4 times greater than that found in control rats. Protein, DNA, RNA contents in the pancreas, pancreatic wet weight per 100 micrograms DNA and RNA/DNA ratio were also found significantly elevated in experimental group as opposed to the control group. Basal plasma levels of cholecystokinin (CCK) and gastrin were measured to delineate the influence of hormonal response on the pancreatic growth in ileo-caecal resected rats and were found not significantly increased after ileo-caecal resection. The data suggest that the enlargement of pancreas in ileo-caecal resected rats may be due to hyperplasia and hypertrophy of pancreatic cells; alternatively, the pancreatic growth may have been influenced by the bile acid deficiency and the reduction or release of an inhibitory factor present in the ileum of rats.     

Elevation of Basal Protein Kinase C Activity Increases Ethanol Sensitivity of GABAA Receptors in Rat Hippocampal CA1 Pyramidal Neurons

Abstract: The ability of ethanol to enhance GABA_A receptor function remains controversial; conflicting observations have been made even in the same brain region, and when using apparently similar methodologies. In this study we characterized a single protocol variable, the initial incubation temperature of brain slices, that had dramatic effects on the ethanol sensitivity of GABA_A inhibitory postsynaptic currents (IPSCs) recorded from rat hippocampal CA1 pyramidal neurons. Incubation of hippocampal slices at relatively low temperatures (11–15°C) immediately after slice preparation significantly affected a number of physiological and biochemical parameters. Such slices showed a decrease in extracellular inhibitory postsynaptic potential amplitude, a significant increase in the ethanol sensitivity of GABA_A IPSCs in CA1 pyramidal neurons, no change in pentobarbital or flunitrazepam potentiation of IPSCs, and an increase in basal protein kinase C (PKC) activity relative to slices incubated at 31–33°C. In addition, the increase in ethanol sensitivity of GABA_A IPSCs was blocked by chelerythrine, a selective inhibitor of PKC. These results suggest that differences in hippocampal slice incubation protocols may have contributed to the disparate results of previous investigations of ethanol modulation of GABA_A receptor-mediated synaptic transmission in the rat hippocampus. In addition, these findings provide further evidence that PKC activity positively modulates the interaction between ethanol and GABA_A receptors in the mammalian brain.     

Differential cardiorespiratory response to combined exercise with different combinations of forearm and calf exercise

The purpose of this study was to examine whether cardiorespiratory responses to combined rhythmic exercise (60 contractions · min^–1) was affected by different combinations of upper and lower limb exercise in seven healthy women. Six different rhythmic exercises were compared: 6-min rhythmic handgrip at 10% of isometric maximal voluntary contraction (MVC) (H10); 6-min rhythmic plantar flexion at 10% MVC (P10); exhausting rhythmic handgrip at 50% MVC (H50); exhausting rhythmic plantar flexion at 50% MVC (P50); H50 was added to P10 (P1OH50); and P50 was added to H10 (H10P50). Exercise duration, after handgrip was combined with plantar flexion (P10H50), was shorter than that of H50, although the exercise duration of HIOP50 was not significantly different from P50. No significant difference was found between the difference from rest in oxygen uptake ( O₂) during H10P50 and the sum of O₂ during H10 and P50. Also, the differences from rest in forearm blood flow ( FBF) and calf blood flow ( CBF) during H10P50 were not significantly different from FBF in H10 and from CBF in P50. In contrast, O₂ in P10H50 was lower than the sum of O₂ in P10 and H50 (P < 0.05), and J FBF in P10H50 was lower than that in H50 (P < 0.05) , while CBF was not significantly different between P1OH50 and P10. The changes in heart rate from rest (d HR) during the combined exercises were lower than the sums of HR in the corresponding single exercises (P < 0.05). These results demonstrated an inhibitory summation of several cardiorespiratory responses to combined exercise resulting in a reduction in exercise performance which would seem to occur easily when upperlimb exercise is added to lower limb exercise.     

Effect of spore concentration on germination and autotropism inTrichoderma hamatum

Summary The effect of spore concentration on spore germination and germtube growth ofTrichoderma hamatum on water agar and on potato dextrose agar (PDA) was studied. Increasing inoculum size up to 10⁹ spores/plate on PDA and up to 10⁷ spores/plate on water agar shortened the incubation period required for germtubes emergence and increased germination rate. However, on water agar germination was inhibited at 10⁸ and was completely arrested at 10⁹ spores/plate. Inhibition in germination of 10⁷ spores/plate was observed on water agar when the plates were preincubated with 10⁹ spores/plate for 5 h or more. Addition of glucose and ammonium nitrate to the water agar medium allowed only 25% of the spores to germinate at 10⁹ as compared to 78% at 10⁷ spores/plate after 8 h of incubation. Addition of polysaccharides to the C+N supplemented medium, significantly increased germination up to 84% as compared to 100% on PDA, after 8 h of incubation. Germlings ofTrichoderma hamatum phialospores exhibited positive autotropism and anastamosis on both media. The phenomenon was positively related to inoculum size, being most pronounced at 10⁷ spores/plate.