Supersensitivity of the Cholinergic Muscarinic System in the Rats Brain isInduced by high Concentrations of Cu+2
Transition metals have been described as regulators of receptors function. Here, we studied the effects of chronic administration of Cu2+ or the Cu2+ chelator penicillamine (PA) on the functional and binding properties of the muscarinic receptors (MR) on selected areas of rats brain. Groups of 10 Sprague-Dawley rats were treated daily, for 45 days with either 1) 1mg/Kg CuSO4 (Cu2+), 2) 100 mg/Kg PA, or 3) saline solution. Double T-maze and motility cages were used for behavioral testing and the binding assays were performed using [³H]-QNB or [³H]-N-MSCP as MRs ligands. Cu2+ brain levels were measured in the cerebral cortex by atomic absorption spectrophotometer. Results showed that PA treated rats displayed a significant decrease of locomotors activity (LA) and rearing behavior (RB), but a significant increases in memory efficiency (ME). Cu2+ treated rats displayed diminished RB with no significant changes in LA. Cu2+ treated rats displayed higher MRs density (Bmax) in cortex (C), striatum (S), and hippocampus (H). An increase in Bmax was also observed in PA treated rats, but only in C and S. Finally, Cu2+ tissue concentration was significantly higher in C of both Cu2+ and with PA treated animals. In conclusion, 45 days of Cu2+ or PA treatment induced brain hypercuprosis, which was associated with MR binding supersensitivity; however, change in ME was only observed in PA treated rats suggesting that might be still another factor in these experiments besides Cu2+ (i.e., Zn2+ or PA itself) involved in memory modulation.
| Main Authors: | , , , , , , |
|---|---|
| Format: | Digital revista |
| Language: | English |
| Published: |
Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia
2002
|
| Online Access: | http://ve.scielo.org/scielo.php?script=sci_arttext&pid=S0535-51332002000200006 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|