Allyl isothiocyanates and cinnamaldehyde potentiate miniature excitatory postsynaptic inputs in the supraoptic nucleus in rats.
Allyl isothiocyanates (AITC) and cinnamaldehyde are pungent compounds present in mustard oil and cinnamon oil, respectively. These compounds are well known as transient receptor potential ankyrin 1 (TRPA1) agonists. TRPA1 is activated by low temperature stimuli, mechanosensation and pungent irritants such as AITC and cinnamaldehyde. TRPA1 is often co-expressed in TRPV1. Recent study showed that hypertonic solution activated TRPA1 as well as TRPV1. TRPV1 is involved in excitatory synaptic inputs to the magnocellular neurosecretory cells (MNCs) that produce vasopressin in the supraoptic nucleus (SON). However, it remains unclear whether TRPA1 may be involved in this activation. In the present study, we examined the role of TRPA1 on the synaptic inputs to the MNCs in in vitro rat brain slice preparations, using whole-cell patch-clamp recordings. In the presence of tetrodotoxin, AITC (50μM) and cinnamaldehyde (30μM) increased the frequency of miniature excitatory postsynaptic currents without affecting the amplitude. This effect was significantly attenuated by previous exposure to ruthenium red (10μM), non-specific TRP channels blocker, high concentration of menthol (300μM) and HC-030031 (10μM), which are known to antagonize the effects of TRPA1 agonists. These results suggest that TRPA1 may exist at presynaptic terminals to the MNCs and enhance glutamate release in the SON.
Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
Toru
T
Yokoyama
Toyoaki
T
Ohbuchi
Takeshi
T
Saito
Yuka
Y
Sudo
Hiroaki
H
Fujihara
Kouichiro
K
Minami
Toshihisa
T
Nagatomo
Yasuhito
Y
Uezono
Yoichi
Y
Ueta
D000171:Acrolein / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D017487:Ankyrins / Q000037:antagonists & inhibitors; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects*; D066298:In Vitro Techniques; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects; D017879:Isothiocyanates / Q000494:pharmacology*; D008297:Male; D055369:Miniature Postsynaptic Potentials / Q000187:drug effects*; D010477:Perfusion; D051381:Rats; D017208:Rats, Wistar; D013495:Supraoptic Nucleus / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels / Q000037:antagonists & inhibitors
D017487:Ankyrins; D015220:Calcium Channels; D017879:Isothiocyanates; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels; C480976:Trpa1 protein, rat; D000171:Acrolein; C004471:allyl isothiocyanate; C012843:cinnamaldehyde; D002118:Calcium