TOPICS
DATE
March 25, 2022
SHARE

March 25 2022

Docosahexaenoic Acid Potently Inhibits the Prostanoid TP Receptor-Mediated Contractile Response of Tracheal Smooth Muscle

Partial clarification of the mechanism underlying the ameliorative effect of docosahexaenoic acid on bronchial asthma

A research group led by Professor Yoshio Tanaka of the Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, has reported that docosahexaenoic acid selectively and potently inhibited prostanoid TP receptor (*1)-mediated contraction of tracheal smooth muscle. The results of this research were published in the journal “Biological and Pharmaceutical Bulletin” in February 2022.
Dr. Keisuke Obara
A research group led by Professor Yoshio Tanaka of the Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, has reported that docosahexaenoic acid selectively and potently inhibited prostanoid TP receptor (*1)-mediated contraction of tracheal smooth muscle. The results of this research were published in the journal “Biological and Pharmaceutical Bulletin” in February 2022.
Key points
  • The long-term intake of docosahexaenoic acid (DHA) has been reported to improve bronchial asthma by inhibiting the production of inflammatory substances. However, the immediate effects of DHA on the contractile response of tracheal smooth muscle have yet to be investigated.
  • In this study, the researchers found that DHA potently and immediately inhibited the contractile response of tracheal smooth muscle induced by U46619, a stable derivative of thromboxane A2 (TXA2) (*2), and prostaglandin F (PGF) (*2), without affecting the contractile response induced by acetylcholine, histamine, or leukotriene D4 (LTD4).
  • These findings indicate that DHA may ameliorate the bronchial asthma associated with increased levels of TXA2 and PGF by immediately inhibiting TXA2– and PGF-induced hypercontraction of tracheal/bronchial smooth muscle in addition to its anti-inflammatory effects.
Dr. Keisuke Obara
Summary
Docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid found in fish oil, has been attracting considerable attention as a health food constituent. The long-term intake of DHA has been reported to improve bronchial asthma by inhibiting the production of inflammatory substances.
To date, however, the immediate effects on the contractile response of tracheal smooth muscle have yet to be studied.
To clarify the immediate effects of DHA on the contractile response of tracheal smooth muscle, a research group led by Professor Yoshio Tanaka, Lecturer Keisuke Obara, and Assistant Professor Kento Yoshioka at the Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, examined the effect of DHA on the contractile response of tracheal smooth muscle isolated from guinea pigs.
Their findings revealed that DHA potently and immediately inhibits the contractile response of tracheal smooth muscle induced by U46619, a stable derivative of thromboxane A2 (TXA2), and prostaglandin F (PGF), without affecting the contractile response induced by acetylcholine, histamine, or leukotriene D4 (LTD4).
These findings indicate that DHA may ameliorate the bronchial asthma associated with increased levels of TXA2 and PGF by immediately inhibiting TXA2– and PGF-induced hypercontraction of tracheal/bronchial smooth muscle (Fig. 1) in addition to its anti-inflammatory effects.

Terminology
(*1) Prostanoid TP receptor
A receptor that shows high affinity for thromboxane A2. Antagonists of the prostanoid TP receptor are clinically indicated for the treatment of asthma.
(*2) Thromboxane A2 (TXA2) and prostaglandin F (PGF)
Prostanoids that produce during inflammation. Their production is reported to be increased in patients with bronchial asthma and during asthma attacks.
Summary
Docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid found in fish oil, has been attracting considerable attention as a health food constituent. The long-term intake of DHA has been reported to improve bronchial asthma by inhibiting the production of inflammatory substances.
To date, however, the immediate effects on the contractile response of tracheal smooth muscle have yet to be studied.
To clarify the immediate effects of DHA on the contractile response of tracheal smooth muscle, a research group led by Professor Yoshio Tanaka, Lecturer Keisuke Obara, and Assistant Professor Kento Yoshioka at the Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Toho University, examined the effect of DHA on the contractile response of tracheal smooth muscle isolated from guinea pigs.
Their findings revealed that DHA potently and immediately inhibits the contractile response of tracheal smooth muscle induced by U46619, a stable derivative of thromboxane A2 (TXA2), and prostaglandin F (PGF), without affecting the contractile response induced by acetylcholine, histamine, or leukotriene D4 (LTD4).
These findings indicate that DHA may ameliorate the bronchial asthma associated with increased levels of TXA2 and PGF by immediately inhibiting TXA2- and PGF2α-induced hypercontraction of tracheal/bronchial smooth muscle (Fig. 1) in addition to its anti-inflammatory effects.

Terminology
(*1) Prostanoid TP receptor
A receptor that shows high affinity for thromboxane A2. Antagonists of the prostanoid TP receptor are clinically indicated for the treatment of asthma.,br>
(*2) Thromboxane A2 (TXA2) and prostaglandin F (PGF)
Prostanoids that produce during inflammation. Their production is reported to be increased in patients with bronchial asthma and during asthma attacks.

Figure 1: A Schematic Summary of This Study

Figure 1: A Schematic Summary of This Study

Journal Name:
Biological and Pharmaceutical Bulletin Vol. 45, No. 2, 240–244 (February 1st, 2022)

Author(s):
Keisuke Obara, Rikako Inaba, Mirai Kawakita, Montserrat De Dios Regadera, Tomomi Uetake, Azusa Murata, Nanako Nishioka, Kota Kuroki, Kento Yoshioka, Yoshio Tanaka

DOI Number:10.1248/bpb.b21-00905

READ MORE RESEARCH NEWS - Pharmaceutical Sciences

@ Toho University