Antihypertensive effect of betaxolol, a cardioselective .BETA.-adrenoceptor antagonist, in experimental hypertensive rats.

Bessho, Hideki; Suzuki, Junko; Narimatsu, Akihiro; Tobe, Akihiro

doi:10.1254/fpj.95.6_347

Cited by 8 publications

(6 citation statements)

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“…This conclusion is supported by studies in other vascular beds where betaxolol has been confirmed to produce vasodilatation through a Ca# + channel blocking mechanism independently of its β " -selective adrenergic antagonist action (Bessho et al, 1990).…”

Section: Introductionmentioning

confidence: 62%

“…Betaxolol has no intrinsic sympathomimetic activity, and membrane stabilising or local anaesthetic effects do not seem to play a role in the relaxation action of betaxolol (Brooks and Gillies, 1992 ;Beresford and Heel, 1986). Bessho et al (1990) reported the effects of betaxolol on isolated rat aortic strips and the modes of action were investigated. They suggested that betaxolol had a direct vasodilating action, possibly due to inhibition of Ca# + influx across the smooth muscle cell membrane.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Betaxolol, Timolol and Nimodipine on Human and Pig Retinal Arterioles

Su²,

Cringle³

et al. 1998

Experimental Eye Research

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Section: Introductionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Effect of Betaxolol, Timolol and Nimodipine on Human and Pig Retinal Arterioles

Su²,

Cringle³

et al. 1998

Experimental Eye Research

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“…In the previous in vivo observations with the hindlimb perfusion model in dogs, the vasodi lating action of betaxolol was also 3 times less potent than that of papaverine (6). Bunitrolol is known to lower the blood pressure of renal hypertensive dogs, like betaxolol, by single oral administration (13), and this anti hypertensive action may be partly due to its direct vasodilating action (16).…”

Section: Discussionmentioning

confidence: 91%

“…These data suggest that betaxolol might have a certain effect other than 8-adreno ceptor antagonism. In fact, betaxolol induced an increase in blood flow by intraarterial administration (6) and a decrease in total peripheral resistance by intravenous adminis tration in anesthetized dogs (14).…”

Section: Betaxolol [(±)-1-[4-[2-(cyclopropylmethoxy) Ethyl]phenoxy]-3mentioning

confidence: 94%

Vascular effects of betaxolol, a cardioselective .BETA.-adrenoceptor antagonist, in isolated rat arteries.

1991

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ABSTRACT-The effects of betaxolol on isolated rat arteries and the modes of action were investigated. Betaxolol (10-5 -10-3 M) relaxed the 80 mM K+-induced contrac tion of aortic strips concentration-dependently. The 50% inhibitory concentration of betaxolol in the K+-induced contraction was 3 times higher than that of papaverine and about 3 times lower than that of bunitrolol. The relaxations by betaxolol were also demonstrated in renal, mesenteric and femoral arteries. Betaxolol (3 X 106 M 10-4 M) produced rightward parallel shifts of the concentration-response curves for Ca 2+ in the K+-depolarized aortic strips. On the other hand, betaxolol produced downward shifts as well as rightward shifts of the concentration-response curves for norepinephrine, 5-HT and angiotensin II. In K+-depolarized aortic strips, the cyto solic Ca 2+ concentration measured with a fluorescent indicator, fura-2, was decreased by betaxolol (10-4 M) almost concomitantly with the loss of tention. An elevation of external Ca 2+ from 2.5 mM to 10 mM restored both the cytosolic Ca2+ concentration and tention. The relaxations of arteries induced by betaxolol were not influenced by glybenclamide, methylene blue, indomethacin or removal of the endothelium. These results suggest that betaxolol possesses a direct vasodilating action, and the action may be due to the inhibition of Ca 2+ influx across the cell membrane. Betaxolol [(±)-1-[4-[2-(cyclopropylmethoxy) ethyl]phenoxy]-3-(isopropylamino)-2-propanol]hydrochloride is a cardioselective ,Q-adreno ceptor antagonist with no intrinsic sympatho mimetic activity and little membrane stabiliz ing activity (1, 2). In patients with essential hypertension, betaxolol was shown to produce potent and long lasting antihypertensive effects by once daily therapy (2, 3) because of high bioavailability and a long elimination half life (4, 5).In previous laboratory studies, we (6-8) and other workers (9) have shown that a single oral administration of betaxolol lowers the blood pressure of various hypertensive models, i.e., spontaneously hypertensive rats, renal hypertensive rats, deoxycorticosterone/ saline hypertensive rats and renal hypertensive dogs. However, other 8-adrenoceptor anta gonists such as atenolol are unlikely to pro duce antihypertensive effects by single admin istration in these hypertensive models (10 13). These data suggest that betaxolol might have a certain effect other than 8-adreno ceptor antagonism. In fact, betaxolol induced an increase in blood flow by intraarterial administration (6) and a decrease in total peripheral resistance by intravenous adminis tration in anesthetized dogs (14).Although / -adrenoceptor antagonism of be taxolol has been well studied (2), the effects of betaxolol on isolated arteries have not yet

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“…pCa 5. suggest that the decrease in Ca 2+ sensitivity may also be partly responsible for the relaxation caused by betaxolol and propranolol in isolated smooth muscle as well as Ca 2+ antagonistic action. It has been shown that betaxolol, but not propranolol, when injected intraarterially, increased the femoral artery blood flow in anesthetized dogs [12]. The discrepancy between the effects of betaxolol and propranolol appears to be dependent on the potency of their betae-adrenoceptor blocking activities, because betaxolol has little effect on beta2-adrenoceptor blocking action.…”

Section: Discussionmentioning

confidence: 96%

Contrasting effects of betaxolol and propranolol on Ca2+-activated contractions in skinned fibers from canine coronary arteries and ventricular muscles

Kitada

1996

Cardiovasc Drug Ther

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The effects of some beta-adrenoceptor antagonists (atenolol, betaxolol, bunitrolol, labetalol, pindolol, and propranolol) on Ca2+ (pCa 5.8)-activated tension development in chemically skinned fibers from canine coronary artery and right ventricular trabeculae were studied. In skinned coronary arteries, Ca(2+)-activated tension development was decreased by betaxolol and propranolol at concentration of more than 10(-5) and 10(-4) M, respectively. The pCa-tension relationships were shifted to the right and down by betaxolol. In contrast, in skinned cardiac muscle Ca(2+)-activated tension development was increased by betaxolol and propranolol at the same range of concentrations as in coronary arteries, with no change in maximum tension. The pCa-tension relation was shifted to the left by betaxolol. Other beta-adrenoceptor antagonists (atenolol, bunitrolol, labetalol, and pindolol) had no effect on Ca(2+)-induced contraction in either muscle type. These results indicate that among beta-adrenoceptor antagonists, only betaxolol and propranolol can directly modulate the Ca2+ sensitivity of myofilaments and have opposite effects on the contractile system in canine cardiac and vascular smooth muscle.

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Antihypertensive effect of betaxolol, a cardioselective .BETA.-adrenoceptor antagonist, in experimental hypertensive rats.

Cited by 8 publications

References 0 publications

Effect of Betaxolol, Timolol and Nimodipine on Human and Pig Retinal Arterioles

Effect of Betaxolol, Timolol and Nimodipine on Human and Pig Retinal Arterioles

Vascular effects of betaxolol, a cardioselective .BETA.-adrenoceptor antagonist, in isolated rat arteries.

Contrasting effects of betaxolol and propranolol on Ca2+-activated contractions in skinned fibers from canine coronary arteries and ventricular muscles

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