Supersensitivity of the cholinergic muscarinic system in the rat's brain is induced by high concentrations of Cu+2
Invest. clín
; 43(2): 107-117, jun. 2002.
Article
in En
| LILACS
| ID: lil-330975
Responsible library:
BR1.1
RESUMO
Transition metals have been described as regulators of receptor's 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 rat's brain. Groups of 10 Sprague-Dawley rats were treated daily, for 45 days with either 1) 1 mg/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 MR's 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 locomotor's 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 MR's 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.
Full text:
1
Index:
LILACS
Main subject:
Brain Chemistry
/
Receptors, Muscarinic
/
Copper Sulfate
/
Nerve Tissue Proteins
Limits:
Animals
Language:
En
Journal:
Invest. clín
Journal subject:
Biologia
/
MEDICINA
/
Relatos de Casos
Year:
2002
Type:
Article