Biomedical subjects

Mahadev Murthy

Publications and source records attributed to Mahadev Murthy.

3 recordsLinked to original sources

PubMed2002

Cognitive deficits in docosahexaenoic acid-deficient rats.

This study investigated the influence of brain docosahexaenoic acid (DHA) deficiency on simple and complex olfactory-based learning and memory in 2nd generation (F2) adult male rats. Rats raised and maintained on either an n-3-adequate or an n-3-deficient diet were tested for acquisition of an olfactory learning set and an olfactory memory task, and for motivation to obtain a water reward. Despite a 76% decrease in brain DHA, n-3-deficient rats were able to acquire most simple 2-odor discrimination tasks but were deficient in the acquisition of a 20-problem olfactory learning set. This deficit could not be attributed to changes in sensory capacity but, instead, appeared to represent a deficit in higher order learning.

Animals↗

PubMed2002

A decrease in cell size accompanies a loss of docosahexaenoate in the rat hippocampus.

Rats raised on n-3 essential fatty acid deficient diets demonstrate spatial memory deficits. To investigate neuroanatomical correlates of these deficits, morphological analysis of the hippocampus were carried out. Adult, female rats were raised for three generations on n-3 deficient or n-3 supplemented diets. Two n-3 deficient diets contained adequate linoleic acid (LA), or high linoleic acid (high LA), and two supplemented diets contained LA supplemented with alpha-linolenic acid (+LNA), or linoleic supplementation with alpha-linolenic and docosahexaenoic acids (+LNA/DHA). The total fatty acid composition of the hippocampus revealed a profound loss (90%) in docosahexaenoic acid (DHA) in the hippocampi of LA and high LA animals compared to those on +LNA and +LNA/DHA diets with a reciprocal increase in docosapentaenoic acid (DPAn-6) in all phospholipid species. The volume, density, total number, and cell body size of neurons in CA1-3, granular and hilar layers of the hippocampus were measured at septal and temporal locations using unbiased stereology. No differences were detected in any of these measures except for in cell body size; CA1 pyramidal neurons in the LA group were significantly (p < 0.04) smaller than neurons in the +LNA/DHA group at the septal location.

Animals↗

PubMed2002

Differential effects of n-3 fatty acid deficiency on phospholipid molecular species composition in the rat hippocampus.

In this study, we have examined the effects of n-3 fatty acid deficient diets on the phospholipids (PL) molecular species composition in the hippocampus. Female rats were raised for two generations on diets containing linoleic acid (18:2n-6), with or without supplementation of alpha-linolenic acid (18:3n-3) or 18:3n-3 plus docosahexaenoic acid (22:6n-3). At 84 days of age, the hippocampal phospholipids were analyzed by reversed phase HPLC-electrospray ionization mass spectrometry. Depleting n-3 fatty acids from the diet led to a reduction of 22:6n-3 molecular species in phosphatidylcholine (PC), phosphatidylethanolamine (PE), PE-plasmalogens (PLE), and phosphatidylserine (PS) by 70-80%. In general, 22:6n-3 was replaced with 22:5n-6 but the replacement at the molecular species level did not always occur in a reciprocal manner, especially in PC and PLE. In PC, the 16:0,22:6n-3 species was replaced by 16:0,22:5n-6 and 18:0,22:5n-6. In PLE, substantial increases of both 22:5n-6 and 22:4n-6 species compensated for the decreases in 22:6n-3 species in n-3 fatty acid deficient groups. While the total PL content was not affected by n-3 deficiency, the relative distribution of PS decreased by 28% with a concomitant increase in PC. The observed decrease of 22:6n-3 species along with PS reduction may represent key biochemical changes underlying losses in brain-hippocampal function associated with n-3 deficiency.

Analysis of Variance↗