Chronic but not acute immobilization stress stably enhances hippocampal CA1 metabotropic glutamate receptor dependent Long-Term Depression.
Acute stress has been shown to facilitate but not increase metabotropic glutamate receptor (mGluR) mediated Long-Term Depression (LTD) in the hippocampus. However, the effect of chronic stress on mGluR dependent LTD has not been investigated. Moreover, whether stress leads to a transient modification LTD threshold or a more stable change in synaptic plasticity needs to be addressed. In the present study, we have explored the effects of both a ten-day long and a single day immobilization stress protocol on mGluR-LTD at the CA3:CA1synapse in the hippocampus of adult male Sprague-Dawley rats, a day after applying stress. Bath application of the selective group 1 mGluR agonist (S)-3,5-dihydroxyphenylglycine (DHPG) promoted robust LTD in hippocampal slices from control (i.e. un-stressed) animals. Administration of immobility stress for two hours per day for ten days significantly elevated this LTD to a level almost twice that of control, when observed 24h following the last stress event. Acute stress i.e. a single day of two hours of immobilization, however, failed to significantly enhance LTD, 24h later. These results demonstrate for the first time, that repeated exposure to stress, but not a single stress event, is required to bring about a stable alteration in mGluR mediated synaptic plasticity.
Department of Electrophysiology, Biolab, TCG Lifesciences Pvt. Ltd., Bengal Intelligent Park, Tower-B, Block-EP & GP, Sector-V, Salt Lake Electronic Complex, Kolkata, 700091, India. Electronic address: tathagata.sengupta@tcgls.com.
Tathagata
T
Sengupta
Department of Electrophysiology, Biolab, TCG Lifesciences Pvt. Ltd., Bengal Intelligent Park, Tower-B, Block-EP & GP, Sector-V, Salt Lake Electronic Complex, Kolkata, 700091, India.
Rishi
R
Das
National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, 560065, India.
Sumantra
S
Chattarji
D000208:Acute Disease; D000818:Animals; D056547:CA1 Region, Hippocampal / Q000378:metabolism; D056654:CA3 Region, Hippocampal / Q000378:metabolism; D002908:Chronic Disease; D007103:Immobilization; D036881:Long-Term Synaptic Depression; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives / Q000494:pharmacology; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism*; D013315:Stress, Psychological / Q000378:metabolism* / Q000503:physiopathology*; D013569:Synapses / Q000502:physiology; D013997:Time Factors
D018094:Receptors, Metabotropic Glutamate; D008734:Methoxyhydroxyphenylglycol; C010117:3,4-dihydroxyphenylglycol
Electrophysiology; Hippocampus; LTD; Stress; mGluR