Chewing rescues stress-suppressed hippocampal long-term potentiation via activation of histamine H1 receptor.
We have previously found in rats that chewing, an active behavioral strategy to cope with a stressful situation, rescues long-term potentiation (LTP) in the hippocampus through activating stress-suppressed N-methyl-D-aspartate (NMDA) receptor function. To further examine the mechanisms underlying this ameliorative effect of chewing, we studied the involvement of the histaminergic system, which has been shown to be activated by mastication, in the LTP of hippocampal slices of rats that were allowed to chew a wooden stick during exposure to immobilization stress. Chewing failed to rescue stress-suppressed LTP in the rats treated with histamine H1 receptor (H1R) antagonist pyrilamine (5 mg/kg, i.p.) before exposure to stress, although administration of pyrilamine did not affect LTP in naive rats and in stressed rats that did not chew. However, when pyrilamine was administrated immediately after exposure to stress, chewing rescued LTP whose magnitude was statistically comparable to that in the rats that chewed without drug treatment. These results suggest that chewing-induced histamine release in the hippocampus and the subsequent H1 receptor activation may be essential to rescue stress-suppressed synaptic plasticity.
Ono
Yumie
Y
Department of Physiology and Neuroscience, Kanagawa Dental College, 82 Inaoka-cho, Yokosuka, Kanagawa 238-8580, Japan. yumie@kdcnet.ac.jp
Kataoka
Tsuyoshi
T
Miyake
Shinjiro
S
Sasaguri
Kenichi
K
Sato
Sadao
S
Onozuka
Minoru
M
D000223:Adaptation, Psychological / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008409:Mastication / Q000502:physiology*; D008569:Memory Disorders / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011969:Receptors, Histamine H1 / Q000187:drug effects / Q000378:metabolism*; D013315:Stress, Psychological / Q000378:metabolism* / Q000503:physiopathology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D006634:Histamine H1 Antagonists; D011969:Receptors, Histamine H1; D011738:Pyrilamine