Anji white tea relaxes precontracted arteries, represses voltage-gated Ca2+ channels and voltage-gated K+ channels in the arterial smooth muscle cells : Comparison with green tea main component (-)-epigallocatechin gallate

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ETHNOPHARMACOLOGICAL RELEVANCE: Tea (Camellia sinensis) is a favorite drink worldwide. Tea extracts and green tea main component (-)-epigallocatechin gallate (EGCG) are recommended for various vascular diseases. Anji white tea is a very popular green tea. Its vascular effect profile, the mechanisms, and the contribution of EGCG to its integrated effect need elucidation.

AIM: To characterize the vasomotion effects of Anji white tea and EGCG, and to explore possible involvement of voltage-gated Ca2+ channels (VGCCs) and voltage-gated K+ (Kv) channels in their vasomotion effects.

MATERIALS AND METHODS: Anji white tea water soaking solution (AJWT) was prepared as daily tea-making process and concentrated to a concentration amounting to 200 mg/ml of dry tea leaves. The tension of rat arteries including aorta, coronary artery (RCA), cerebral basilar artery (CBA), intrarenal artery (IRA), intrapulmonary artery (IPA) and mesenteric artery (MA) was recorded with myographs. In arterial smooth muscle cells (ASMCs) freshly isolated from RCA, the levels of intracellular Ca2+ were measured with Ca2+-sensitive fluorescent probe fluo 4-AM, and Kv currents were recorded with patch clamp. The expressions of VGCCs and Kv channels were assayed with RT-qPCR and immunofluorescence staining.

RESULTS: At 0.4-12.8 mg/ml of dry tea leaves, AJWT profoundly relaxed all tested arteries precontracted with various vasoconstrictors about half with a small transient potentiation on the precontractions before the relaxation. KCl-induced precontraction was less sensitive than precontractions induced by phenylephrine (PE), U46619 and serotonin (5-HT). IPA was less sensitive to the relaxation compared with other arteries. AJWT pretreatment for 1 h, 24 h and 72 h time-dependently inhibited the contractile responses of RCAs. In sharp contrast, at equivalent concentrations according to its content in AJWT, EGCG intensified the precontractions in most small arteries, except that it induced relaxation in PE-precontracted aorta and MA, U46619-precontracted aorta and CBA. EGCG pretreatment for 1 h and 24 h did not significantly affect RCA contractile responses. In RCA ASMCs, AJWT reduced, while EGCG enhanced, intracellular Ca2+ elevation induced by depolarization which activates VGCCs. Patch clamp study showed that both AJWT and EGCG reduced Kv currents. RT-qPCR and immunofluorescence staining demonstrated that both AJWT and EGCG reduced the expressions of VGCCs and Kv channels.

CONCLUSION: AJWT, but not EGCG, consistently induces vasorelaxation. The vasomotion effects of either AJWT or EGCG vary with arterial beds and vasoconstrictors. Modulation of VGCCs, but not Kv channels, contributes to AJWT-induced vasorelaxation. It is suggested that Anji white tea water extract instead of EGCG may be a promising food supplement for vasospastic diseases.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:328

Enthalten in:

Journal of ethnopharmacology - 328(2024) vom: 28. Apr., Seite 117855

Sprache:

Englisch

Beteiligte Personen:

Xu, Xiaojia [VerfasserIn]
Fan, Yingying [VerfasserIn]
Yang, Xiaomin [VerfasserIn]
Liu, Yu [VerfasserIn]
Wang, Yan [VerfasserIn]
Zhang, Jiangtao [VerfasserIn]
Hou, Xiaomin [VerfasserIn]
Fan, Yanying [VerfasserIn]
Zhang, Mingsheng [VerfasserIn]

Links:

Volltext

Themen:

059QF0KO0R
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
76898-47-0
8R1V1STN48
Anji white tea
BQM438CTEL
Catechin
Epigallocatechin gallate
Green tea
Journal Article
Tea
Vasoconstrictor Agents
Vasorelaxation
Voltage-gated Ca(2+) channel
Voltage-gated K(+) channel
Water

Anmerkungen:

Date Completed 15.04.2024

Date Revised 15.04.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.jep.2024.117855

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM36836657X