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K Vasudevan

Publications and source records attributed to K Vasudevan.

9 recordsLinked to original sources
PubMed2002

Antiatherogenic effect of taurine in high fat diet fed rats.

The role of taurine on atherogenesis induced by high fat diet in rats, a species which depends entirely on taurine for conjugation of bile acids has been investigated. Wistar male rats were fed on (p.o.) taurine in addition to high fat diet (11% coconut oil w/w) for 6 months. High fat diet caused significant increase of serum total cholesterol (2 fold), serum triglycerides (92.6%), LDL cholesterol (92.3%) and body weight gain (2.8 fold). Taurine administration significantly reduced serum cholesterol (37%), triglycerides (94.5%), LDL cholesterol (34%), body weight (46%). It also significantly reduced aortic cholesterol and thiobarbituric acid reactive substances and there was a significant increase of reduced glutathione. Taurine significantly increased fecal bile acids which may have resulted in significant decrease of serum cholesterol. Aortic lesion index was significantly decreased in the taurine administered group suggesting the antiatherogenic effect of taurine. It is concluded that taurine attenuated the atherogenesis possibly by its hypocholesterolemic and antioxidant property.

Animals↗
PubMed2000

The neuregulin receptor ErbB-4 interacts with PDZ-containing proteins at neuronal synapses.

Neuregulins regulate the expression of ligand- and voltage-gated channels in neurons and skeletal muscle by the activation of their cognate tyrosine kinase receptors, ErbB 1-4. The subcellular distribution and mechanisms that regulate the localization of ErbB receptors are unknown. We have found that ErbB receptors are present in brain subcellular fractions enriched for postsynaptic densities (PSD). The ErbB-4 receptor is unique among the ErbB proteins because its C-terminal tail (T-V-V) conforms to a sequence that binds to a protein motif known as the PDZ domain. Using the yeast two-hybrid system, we found that the C-terminal region of ErbB-4 interacts with the three related membrane-associated guanylate kinases (MAGUKs) PSD-95/SAP90, PSD-93/chapsyn-110, and SAP 102, which harbor three PDZ domains, as well as with beta(2)-syntrophin, which has a single PDZ domain. As with N-methyl-D-aspartate (NMDA) receptors, ErbB4 interacts with the first two PDZ domains of PSD-95. Using coimmunoprecipitation assays, we confirmed the direct interactions between ErbB-4 and PSD-95 in transfected heterologous cells, as well as in vivo, where both proteins are coimmunoprecipitated from brain lysates. Moreover, evidence for colocalization of these proteins was also observed by immunofluorescence in cultured hippocampal neurons. ErbB-4 colocalizes with PSD-95 and NMDA receptors at a subset of excitatory synapses apposed to synaptophysin-positive presynaptic terminals. The capacity of ErbB receptors to interact with PDZ-domain proteins at cell junctions is conserved from invertebrates to mammals. As discussed, the interactions found between receptor tyrosine kinases and MAGUKs at neuronal synapses may have important implications for activity-dependent plasticity.

Animals↗
PubMed1999

Developmental brain injury associated with abnormal play behavior in neonatally Borna disease virus-infected Lewis rats: a model of autism.

Play behavior, nonsocial exploratory activity, and nonplay social interaction were observed in male juvenile Lewis rats with brain developmental injury following neonatal infection with Borna disease virus (BDV). These behaviors were tested using the 'intruder-resident' paradigm, with social isolation of residents for six days prior to testing. Four experimental pairings of infected (BDV) and uninfected (NL) rats were studied as follows: NL-NL; NL BDV; BDV NL; and BDV-BDV (the first member is the resident, the second member is the intruder). Observation of social activities was carried out for 10 min on two consecutive days. Nonsocial exploratory activity (e.g. ambulation and rearing) was similar in BDV and NL residents. Duration of nonplay social investigation (e.g. sniffing, approach, and follow) was higher in BDV residents as compared to NL residents when tested on the first test day. On the second day, all rats showed similar level of nonplay social interaction. When confronted with NL intruders, NL residents exhibited significantly more play behavior compared to the NL-BDV, BDV NL and BDV-BDV pairs, when play behavior was measured by the number of 'pins'. Moreover, irrespective of a type of intruder, NL residents demonstrated higher play soliciting behavior than BDV residents, indicating attenuated readiness to play in BDV-infected rats. The number of pins and play solicitations in BDV-NL pairs significantly increased over the two days of testing, while play activity in NL-BDV pairs declined on the second test day. This pattern suggests that the degree of social reinforcement on the first day of testing affected the level of play on the second day. These data demonstrate deficits in play behavior and other social interactions following BDV-associated developmental brain injury, thus supporting the value of the neonatally BDV-infected rat as an animal model of autism.

Animals↗
PubMed1992

Use of rat jejunum for assay of acetylcholine.

Experiments were carried out to determine the advantage in using isolated rat jejunum in the assay of acetylcholine (ACh) in preference to other tissues. Rat jejunum was found to be sensitive to ACh 0.01 micrograms, 5-hydroxytryptamine (5HT) 0.2 to 0.5 microgram and least sensitive to histamine. (Ach greater than 5HT greater than histamine).

Acetylcholine↗
PubMedDate not supplied

Influence of intragastric perfusion of aqueous spice extracts on acid secretion in anesthetized albino rats.

BACKGROUND: The effect of spices on gastric acid secretion is variable. Their mechanism of action is also not well established. AIM: To study the effect of spices on gastric acid secretion in anesthetized rats. METHODS: Aqueous extracts (10% w/v) of red pepper (Capsicum annuum), fennel (Foeniculum vulgare), omum/ajwan (Carum copticum), cardamom (Elettaria cardamomum), black pepper (Piper nigrum), cumin (Cuminum cyminum) and coriander (Coriandrum sativum) were prepared. The stomach of pentobarbitone-anesthetized rats was perfused at 0.15 mL/min with aqueous extracts of spice or acetylcholine (1 microgram/mL or 10 micrograms/mL solutions, in 40 min blocks, twice in each experiment bracketed by saline perfusions. The acid content in the samples was estimated by titration with 0.1N NaOH with phenolphthalein as indicator. Atropine 1 microgram/mL was added to the perfusion fluid in 28 experiments. In 32, acute gastric mucosal injury was induced by leaving aspirin 125 mg/Kg in the stomach for 2 h before perfusion. RESULTS: All the spices tested increased acid secretion in the following declining order: red pepper, fennel, omum, cardamom, black pepper, cumin, coriander. Red pepper increased acid secretion (mean [SEM] 0.93 [0.16] mL 0.1N HCl) to about 7 times the basal secretion (0.14 [0.05]; p < 0.005). The increase in acid secretion by the other spices was as follows: fennel 0.42 (0.11) mL 0.1 N HCl from basal secretion (0.12 [0.03]) (p < 0.02); omum 0.33 (0.05) from 0.09 (0.02) (p < 0.01); cardamom 0.28 (0.04) from 0.10 (0.03) (p < 0.005); black pepper 0.19 (0.03) from 0.04 (0.01) (p < 0.005); cumin 0.12 (0.02) from 0.08 (0.01) (p < 0.05); coriander 0.18 (0.03) from 0.09 (0.02) (p < 0.005). Atropine abolished the acid secretion induced by acetylcholine and significantly reduced acid induction by red pepper, omum and coriander, but not that by fennel. In experiments with aspirin-induced mucosal injury the basal acid secretion was low; acid secretion by red pepper and fennel was reduced significantly, but not that by acetylcholine. Cumin and coriander increased acid secretion in injured stomachs. CONCLUSION: The spices tested increased gastric acid secretion, in some by a cholinergic mechanism but by other mechanism(s) as well. Red pepper produced maximum increase in acid secretion, but this was significantly reduced in injured stomachs. Cumin and coriander increased gastric secretion in injured stomachs.

Acetylcholine↗