Noriyoshi Kajimoto

Metabolism and calcium antagonism of sodium alginate oligosaccharides

Sodium alginate oligosaccharides (NaAOs) consisting of a mixture of eight oligosaccharides have previously been reported to lower blood pressure. We investigated in this study the excretion of NaAOs into the urine or feces, and attempted to elucidate the mechanism for lowering blood pressure by using isolated mesenteric arteries from the rabbit. The recovery rate of P8, which is the main component of NaAOs, was 5.2% and 58.9% over 48 hours in the urine and feces, respectively. The mechanism for lowering blood pressure appeared to be NaAOs having calcium antagonist activity, especially voltage-operated calcium channels. Our results suggest that NaAOs are substantially excreted into the feces, although some of them may be absorbed internally, exerting antagonist activity towards the calcium channels, especially voltage-operated calcium channels.

Role of ATP and Related Purine Compounds on Urethral Relaxation in Male Rabbits

Background Non‐adrenergic, non‐cholinergic (NANC) relaxation evoked by electrical field stimulation (EFS) has been observed in the urethra, with nitric oxide (NO) considered the agent most probably mediating this effect. However, Burnstocks purinergic hypothesis suggests that ATP and related purine compounds are neurotransmitters in NANC relaxation, although the physiological and pharmacological effects of ATP and related purine compounds in the urethra have been little studied.

Impaired heart function and noradrenaline release after ischaemia in stroke-prone spontaneously hypertensive rats.

1. Stroke‐prone spontaneously hypertensive rats (SHRSP) are a strain of rat that exhibit severely high blood pressure and stroke attacks at an early age, but their heart function in vitro has seldom been studied in detail. Although the activity of the sympathetic nervous system is known to increase after myocardial ischaemia, there is little information about the cardiac release of noradrenaline (NA) associated with heart function after ischaemia in SHRSP. The aim of the present study was to examine heart function and cardiac NA release after ischaemia in SHRSP.

CHANGES OF ENDOTHELIAL FUNCTIONS IN THE CORONARY ARTERY AFTER CHRONIC NITROARGININE FEEDING

1. The effects of chronic NG‐nitro‐L‐arginine (LNA) feeding on the endothelial function in isolated coronary arteries from stroke‐prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar‐Kyoto (WKY) rats were studied.