3H-Muscimol Binding to Membranes of Chick Forebrain: Changes during Development and after Passive Avoidance Training
Little is known of the role of inhibitory neurotransmitters in the chick brain, or how they might be affected by passive avoidance training. Because of this we decided to use 3H-muscimol, a potent GABA-agonist, to investigate the development of GABA receptors and the effects of passive avoidance training on receptor density in chick forebrain. In view of the considerable evidence of hemispheric asymmetry of avian brain function our experiments were also designed to examine whether any changes in 3H-muscimol binding might be lateralized. For the developmental study, forebrains from chicks aged from 9 days prehatch (12 days in ovo) to 21 days post hatch, were dissected into left and right hemispheres and stored at -20°C under buffer. For passive avoidance training, chicks at 24–36 hours after hatching were trained to avoid pecking at a bead coated with methyl anthranilate (MeA) using the method of Rose et al. (1980). At intervals after training (10, 30 and 180 minutes), the brains were divided into anterior and posterior forebrain roof and forebrain base and then subdivided into left and right hemispheres. Washed membrane preparations were assayed in 50mM Tris-HCl buffer pH 7.3 containing 55 nmol 1-1 3H-muscimol (and 10 μm GABA to estimate non-specific binding) and expressed as pmol muscimol bound per mg membrane protein.
KeywordsPassive Avoidance Forebrain Base Gaba Receptor Inhibitory Neurotransmitter Hemispheric Asymmetry
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