Oblongine chloride may have potential haemodynamic effects, it can cause a dose-dependent reduction of systolic and diastolic blood pressure, and that these effects are not mediated by α2-adrenergic receptor stimulation.

Oblongine chloride (3 x 10(-5)-10(-3) M) caused concentration-dependent relaxation of ileum, an effect which was not blocked by propranolol (10(-6) M) alone or in combination with prazosin (3 x 10(-8) M), or by indomethacin (10(-6) M), but was reduced by desensitization of the preparation by prior exposure to 3 x 10(-5) M ATP and, at high concentrations of Oblongine, by a combination of propranolol and yohimbine (3 x 10(-6) M). 3. Oblongine chloride (10(-5)-3 x 10(-3) M) caused concentration-dependent relaxation of epinephrine-precontracted pulmonary artery. This effect was not affected by propranolol or by indomethacin but was significantly attenuated by pretreatment with 3 x 10(-5) M ATP and potentiated by pretreatment with quinacrine (10(-5) M). 4. Oblongine chloride (10(-5) M-3 x 10(-3) M) caused concentration-dependent increase in the contractility but did not affect the rate of the atrium. Similar effects were obtained with isolated perfused heart except that large concentrations of Oblongine (10(-3), 3 x 10(-3) M) inhibited both contractility and rate of the heart.