| Abstract No.: | A-B1046 |
| Country: | Canada |
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| Title: | BETA-ADRENERGIC MODULATION OF METAPLASTICITY |
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| Authors/Affiliations: | 1 Gustavo Tenorio*; 1 Peter Nguyen;
1 University of Alberta, Edmonton, AB, Canada
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| Content: | Objectives: We asked whether prior, brief activation of beta-adrenergic receptors (β-ARs) can enhance induction of future long-lasting LTP ( “late LTP”, L-LTP). To do this, we use isoproterenol (ISO,1 µM), a specific β-AR agonist, paired with a subthreshold electrical stimulation (1x100Hz).
Materials and Methods: Animals: Female C57BL/6 mice (aged 8-13 weeks; Charles River, Montreal, Canada) were used for all experiments.
Electrophysiology: Following cervical dislocation and decapitation of mice, hippocampi were isolated and transverse slices (400 μM) were cut and transferred to an interface recording chamber maintained at 28°C. Oxygenated artificial cerebrospinal fluid (ACSF) was used for dissection and perfusion. Slices were allowed to recover from slicing for at least an hour before recordings were attempted. Field excitatory postsynaptic potentials (fEPSPs) were recorded with a microelectrode situated in stratum radiatum of area CA1 after stimulation of Schaffer collaterals. Electrical stimulation protocol used was 1x100Hz
(1s duration).
Drugs: Isoproterenol 1µM;
AP5 50µM
Propranolol 50µM
Anisomycin 40µM
Results:We show here that after washing out ISO from the bath for an hour, L-LTP can still be achieved by applying 1x100Hz stimulation. This L-LTP is dependent on β-ARs and NMDARs. Also, the presence of anisomycin in the bath after β-AR-activation by ISO does not impair L-LTP and it lasts for at least 6hrs. However, when ISO is washed out for 2 hours the L-LTP is gone.
Conclusion: Prior activation of β-ARs lowers the threshold for future L-LTP induction and initiates the cellular mechanisms underlying metaplasticity.
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