1. The preventive effects of
atherosclerosis and
hyperlipidemia of
monatepil ([(+-)-N-(6,11-dihydrodibenzo [b,e]thiepin-11-yl)-4-(4-fluorophenyl)-1-
piperazine-butanamide+ + +]monomaleate ,
AJ-2615, CAS 103377-41-9), a new
antihypertensive drug with potent
calcium antagonistic and alpha 1-adrenoceptor blocking activities, were investigated in Japanese monkeys (Macaca fuscata) fed with a
cholesterol-rich diet (2%
cholesterol + 6%
corn oil) and compared with those of
prazosin. 2. The dose of
monatepil selected (30 mg/kg/d, p.o., 6 months) was the plasma concentration dose level of
antihypertensive therapy and that of
prazosin (2 mg/kg twice daily, p.o., 6 months) was the dose where hypolipidemic effect in
cholesterol-fed monkeys has been reported. 3. In the
cholesterol diet control group (n = 7), plasma levels of total
cholesterol and
low-density lipoprotein (
LDL) significantly increased and that of
high-density lipoprotein-cholesterol (HDL-C) decreased compared with the normal diet group (n = 5). In the
monatepil group (n = 5), these changes were significantly suppressed. In the
prazosin group (n = 5), these changes were also inhibited but the inhibitory effect was weaker than in the
monatepil group. 4. The
cholesterol content and sudanophilic area in the aorta indicating atheromatous lesions in the
cholesterol-diet fed control group were significantly higher than those in the normal diet control group. In the
monatepil group, these changes were significantly suppressed whereas in the
prazosin group these changes were partially inhibited. 5. In the histological study, aortic lesions characterized by aggregations of foam cells were observed in the
cholesterol-diet control group, while there was little change in the
monatepil group. The anti-atherogenic effect of
prazosin was weaker than that of
monatepil. 6. Coronary atheromatous lesions were found in 4 out of the 7 animals in the
cholesterol-diet control group and 3 out of the 5 animals in
prazosin group. In contrast, no coronary atheromatous lesion was found in the
monatepil group. 7. The treatment with
monatepil did not influence food consumption,
body weight, physical signs or blood biochemistry. 8. The anti-atherosclerotic and plasma
lipid-lowering effects of
monatepil may in part be attributable to its
calcium antagonistic, alpha 1-adrenoceptor blocking, and anti-lipid peroxidation activities. 9. In conclusion,
monatepil is a new class of
antihypertensive agent that possesses anti-atherogenic properties and the ability to reduce plasma
lipid levels, a main risk factor for
atherosclerosis.