Differential Antihypertensive Effects of Oral Doses of Acetylcholine between Spontaneously Hypertensive Rats and Normotensive Rats

Abstract

Acetylcholine (ACh) is a novel antihypertensive food component. Here, we demonstrate the differential effects of oral ACh on high and normal blood pressure in rats. Spontaneously hypertensive rats (SHRs) and Wistar–Kyoto (WKY) rats were administered ACh orally. The blood pressure and heart rate of SHRs were significantly lowered with ACh doses of 10−5 and 10−3 mol/kg body weight (b.w.), and the urinary catecholamine levels were significantly decreased with 10−3 mol/kg b.w. In contrast, oral ACh administration had no effect on WKY rats. This difference was likely caused by differences in sympathetic nervous activity and the baroreflex between strains. Comparison of gene sequences between the two strains revealed Chga mutations, suggesting that changes in the expression of chromogranin A might be involved in the baroreflex in SHRs. Oral ACh had an antihypertensive effect under hypertension but not normotension, indicating that this may be used safely to prevent hypertension.

Antihypertensive Mechanism of Orally Administered Acetylcholine in Spontaneously Hypertensive Rats

“…However, the details of the antihypertensive mechanism of orally administered ACh are unknown. Our latest study revealed a selective BP-lowering effect of orally administered ACh in hypertensive rats, but not in normotensive rats, and indicated the involvement of the suppression of SNA and the dysfunction of the baroreflex [11]. SHRs as an essential hypertension model present excessive SNA [12], as observed in patients with essential hypertension.…”

“…Dysfunction of the baroreflex may be responsible for the specific antihypertensive effect of orally administered ACh under only hypertensive conditions. In a previous study, oral ACh administration had no effect on normotensive Wistar-Kyoto rats [11]. Baroreflex dysfunction is also observed in humans with essential hypertension [21].…”

“…SNA is strongly related to the food functionality of exogenous ACh [10,11]. Therefore, SNA must be accurately measured in living tissues.…”

Evaluation of the Antihypertensive Activity of Eggplant Acetylcholine and γ-Aminobutyric Acid in Spontaneously Hypertensive Rats

“…The concentrations of GABA administered were determined based on reference to the hypotensive effect dose-dependent range for SHR/Izm rats (0.5–50 μmol/kg BW) and by the findings of our preliminary experiments [ 36 ]. ACh concentrations were set at the lowest hypotensive effect dose (10 μmol/kg BW) for SHR/Izm rats [ 37 ].…”

Antihypertensive and Vasorelaxant Effects of Citric Acid and Lemon Juice in Spontaneously Hypertensive Rats: In Vivo and Ex Vivo Studies

“…Eriocitrin and hesperidin: column InertSustain C18 (5 µm, 4.6 × 250 mm, GL Science, Tokyo, Japan), eluent A (5% acetic acid), eluent B (methanol), mobile phase A:B = 70:30 (isocratic), column temperature 40 • C, detection wavelength 280 nm. GABA (AccQ, Tag derivative): column AccQ-Tag (3.9 × 150 mm, Waters, Milford, MA, USA), eluent A (sodium acetate, 30% trimethylamine, phosphoric acid), eluent B (60% acetonitrile), gradient min (B%) = 0 (0), 0.5 (2), 15 (7), 19 (10), 32 (33), 33 (33), 34 (100), column temperature 37 • C, fluorescence detection Ex250 nm EM395 nm. The K and vitamin C contents of lemon juice were determined at the Japan Food Research Laboratories (Tokyo, Japan) using conventional atomic absorption spectrometry and HPLC methods, respectively.…”