Jackson,James; Paulose,C S(Department of Biotechnology, November 19, 1998)
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Abstract:
5-Hydroxytryptamine2A (5-HT2A) receptor kinetics was studied in cerebral cortex and brain stem of streptozotocin (STZ) induced
diabetic rats. Scatchard analysis with [3H] (±) 2,3dimethoxyphenyl-l-[2-(4-piperidine)-methanol] ([3H]MDL100907) in cerebral
cortex showed no significant change in maximal binding (Bmax) in diabetic rats compared to controls. Dissociation constant
(K) of diabetic rats showed a significant decrease (p < 0.05) in cerebral cortex, which was reversed to normal by insulin treatment.
Competition studies of [3H]MDL100907 binding in cerebral cortex with ketanserin showed the appearance of an additional
low affinity site for 5-HT2A receptors in diabetic state, which was reversed to control pattern by insulin treatment. In brain stem,
scatchard analysis showed a significant increase (p < 0.05) in Bmax accompanied by a significant increase (p < 0.05) in Kd.
Competition analysis in brain stem also showed a shift in affinity towards a low affinity State for 5-HT2A receptors. All these
parameters were reversed to control level by insulin treatment. These results show that in cerebral cortex there is an increase
in affinity of 5-HT2A receptors without any change in its number and in the case of brain stem there is an increase in number of
5HT2A receptors accompanied by a decrease in its affinity during diabetes. Thus, from the results we suggest that the increase
in affinity of 5-HT2A receptors in cerebral cortex and upregulation of 5-HT2A receptors in brain stem may lead to altered neuronal
function in diabetes.
The use of laser excitations at two wavelengths, 488 rim and 514 nm, produced by Argon ion laser in
two plants species, Vicia faba (faba bean) and Allium cepa L., is described to compare the mutagenicity and
the spectrum of chromosomal aberrations induced by laser at mitosis. The laser irradiation has been done
at two power levels 200 and 400 mW with power densities 2.25 mW cm 2 and 4.49 mW cm 2 and different
exposure times (10, 20, 30 and 40 min). The effect produced by laser is compared to those of UV rays and
y- radiations. Laser as in the case of other physical and chenucal mutagens causes a dose-dependent decrease
in mitotic chromosomal aberrations at these wavelengths. It is postulated that laser could be used as a new
radiation system for the induction of mutations.
Pyroja,S; Biju,M P; Paulose,C S(Department of Biotechnology, February 11, 1998)
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Abstract:
Effect of pyridoxine on growth, metabolism and cellular activity of
freshwater prawn Macrobrachiuni rosenbergii was studied. Postlarvae
(PL-10) of M. rosenbergii were fed with clam meat containing
various concentrations of pyridoxine. After 30 days RNA and DNA
of the abdominal tissues were estimated. Length, weight and RNA
to DNA ratio increased significantly with increasing concentrations
of pyridoxine. The effect of pyridoxine on the metabolic enzyme,
malate dehydrogenase, was also studied. Vmax showed a significant
decrease and the (Km) showed a significant increase in experimental
groups compared to control.