AIM AND METHODSTo investigate the effect of 2 mg/kg and 10 mg/kg losartan intraperitoneally (i.p) on arterial blood pressure (AP) and heart rate (HR) in rat and the involvement in the activity of habenulas neurons. Glass micropipette was used to record any changes of unit discharging of neurons in LHb and MHb before and after losartan was intraperitoneally injected.

RESULTSAP and HR were not significantly changed by 2 mg/kg losartan (i.p). However, AP was apparently decreased by 10 mg/kg losartan (i.p), but HR was unchanged. After 10 mg/kg losartan (i.p), 66.66% (12/18) unit discharging of neurons in LHb were increased in frequency, and 61.90% (13/21) in MHb were decreased.

CONCLUSIONAP of rat was significantly decreased by 10 mg/kg losartan (i.p). Depressor effect of losartan (i.p) was involved in the excision of neurons in LHb and the inhibition in MHb.

Animals ; Blood Pressure ; drug effects ; Habenula ; drug effects ; physiology ; Losartan ; pharmacology ; Neurons ; drug effects ; physiology ; Rats ; Rats, Wistar

High salt intake increases blood pressure, and dietary salt intake has been clearly demonstrated to be associated with hypertension incidence. Japanese people consume higher amounts of salt than Westerners. It has been reported that miso soup was one of the major sources of daily salt intake in Japanese people. Adding salt is indispensable to make miso, and therefore, in some cases, refraining from miso soup is recommended to reduce dietary salt intake. However, recent studies using salt-sensitive hypertensive models have revealed that miso lessens the effects of salt on blood pressure. In other word, the intake of miso dose not increase the blood pressure compared to the equivalent intake of salt. In addition, many clinical observational studies have demonstrated the absence of a relationship between the frequency of miso soup intake and blood pressure levels or hypertension incidence. The mechanism of this phenomenon seen in the subjects with miso soup intake has not been fully elucidated yet. However, in basic studies, it was found that the ingredients of miso attenuate sympathetic nerve activity, resulting in lowered blood pressure and heart rate. Therefore, this review focused on the differences between the effects of miso intake and those of the equivalent salt intake on sympathetic nerve activity, blood pressure, and heart rate.
Blood Pressure ; drug effects ; physiology ; Heart Rate ; drug effects ; physiology ; Humans ; Soy Foods ; adverse effects ; Sympathetic Nervous System ; drug effects ; physiology

Animals ; Aorta ; drug effects ; physiology ; Blood Pressure ; drug effects ; Cadmium ; toxicity ; Female ; In Vitro Techniques ; Male ; Muscle, Smooth, Vascular ; drug effects ; physiology ; Rabbits ; Vasoconstriction ; drug effects

Animals ; Arteries ; drug effects ; physiology ; Blood Pressure ; drug effects ; Epimedium ; Flavonoids ; pharmacology ; Rats ; Rats, Inbred SHR ; Rats, Wistar

Animals ; Blood Pressure ; drug effects ; Electric Stimulation ; Female ; Habenula ; physiology ; Lidocaine ; pharmacology ; Male ; Raphe Nuclei ; physiology ; Rats ; Rats, Wistar ; Respiration ; drug effects ; Serotonin ; physiology

OBJECTIVETo assess the effect of tetrandrine (Tet) pulmonary targeting microspheres on hypoxic pulmonary hypertension and evaluate its selective action on pulmonary circulation.

METHODSTwenty rats were exposed to hypoxic conditions for 3 weeks. Ten rats were used as normoxic controls. We administered Tet pulmonary targeting microspheres to 10 hypoxic rats and Tet aqueous solution to 10 hypoxic rats and the 10 control rats. Mean pulmonary arterial pressure (mPAP) was measured by a right cardiac catheterization, and mean systemic blood pressure (mSBP) was measured by left femoral catheterization.

RESULTSRats exposed to hypoxia developed pulmonary hypertension. The decrease in mPAP in rats treated with Tet pulmonary targeting microspheres was significantly greater than that in rats receiving Tet aqueous solution (P < 0.05), and the effects were longer with Tet pulmonary targeting microspheres. Moreover, Tet pulmonary targeting microspheres, unlike Tet aqueous solution, did not decrease mSBP.

CONCLUSIONTet pulmonary targeting microspheres were more effective than Tet aqueous solution treating hypoxic pulmonary hypertension and acted selectively on the pulmonary circulation.

Alkaloids ; administration & dosage ; Animals ; Benzylisoquinolines ; Blood Pressure ; drug effects ; Hypertension, Pulmonary ; drug therapy ; Hypoxia ; physiopathology ; Lung ; drug effects ; Male ; Microspheres ; Pulmonary Artery ; drug effects ; physiology ; Rats ; Rats, Wistar

OBJECTIVETo investigate the roles of sympathetic and vagus nerves in hypotension and bradycardia induced by fentanyl.

METHODSFourteen rabbits were divided into 2 groups: normal and vagotomized rabbits. Rabbits were anesthetized, paralyzed, and artificial ventilated. Right renal sympathetic nerve was exposed and prepared for recording electrical activity. Fentanyl was injected intravenously in incremental doses of 1, 4, 15, 30, and 50 microg/kg at 10 minutes intervals.

RESULTSFentanyl significantly reduced the spontaneous activity of renal sympathetic nerve, mean arterial pressure, and heart rate above a total dose of 20 microg/kg in both normal and vagotomized rabbits. However, normal rabbits spontaneous sympathetic nerve activity and mean arterial pressure were more depressed than vagotomized rabbits at total doses of 50 and 100 microg/kg. There were no significant difference in the reduction of heart rate between normal and vagotomized rabbits.

CONCLUSIONFentanyl induction of bradycardia and hypotension in rabbits is mainly due to depression of sympathetic nerve activity.

Analgesics, Opioid ; pharmacology ; Animals ; Blood Pressure ; drug effects ; Fentanyl ; pharmacology ; Heart Rate ; drug effects ; Kidney ; innervation ; Rabbits ; Sympathetic Nervous System ; drug effects ; physiology ; Vagotomy

AIMTo investigate the roles of alpha1 and alpha2 receptors in the nucleus tractus solitarius (NTS) in the carotid baroreflex (CBR) resetting induced by the intracerebroventricular injection (ICV) of histamine (HA).

METHODSThe left and right carotid sinus regions were isolated from the systemic circulation in 25 Sprague-Dawley rats anesthetized with pentobarbital sodium. The intracarotid sinus pressure (ISP) was altered in a stepwise manner. ISP-mean arterial pressure (MAP) relationship curve and its characteristic parameters were constructed by fitting to the logistic function with five parameters. The changes in CBR performance induced by ICV HA and the effects of pretreatment with alpha1 or alpha2 receptor antagonist into the NTS on the responses of CBR to HA were examined.

RESULTSICV HA (60 micromol x L(-1) in 5 microl) significantly shifted the ISP-MAP relationship curve upwards (P < 0.05) and moved the middle part of ISP-Gain relationship curve downwards (P < 0.05), and reduced the MAP range and maximum gain (P < 0.05). The pretreatment with phenoxybenzamine (PBZ, a selective antagonist of alpha1 receptor, 3 micromol x L(-1) in 500 nl) or yohimbine (YOH, a selective antagonist of alpha2 receptor, 2.5 micromol x L(-1) in 500 nl) into the NTS could obviously intensify the above-mentioned changes in CBR performance induced by HA, but the intensive effect of PBZ was less remarkable than that of YOH (P < 0.05).

CONCLUSIONThe intracerebroventricular administration of HA results in a rapid resetting of CBR and a decrease in reflex sensitivity, and the functions of alpha1 and alpha2 receptors in the NTS might weaken CBR resetting induced by ICV HA. Furthermore, alpha2 receptor in the NTS might play an more important role in modulating the responses of CHR to HA.

Animals ; Baroreflex ; drug effects ; Blood Pressure ; Carotid Sinus ; drug effects ; Histamine ; administration & dosage ; pharmacology ; Injections, Intraventricular ; Male ; Rats ; Rats, Sprague-Dawley ; Solitary Nucleus ; drug effects ; physiology

AIMTo study the effect of volume expansion by 0.9% and 1.8% sodium solution on cardiac-renal reflex activity and the role of cardiac-renal reflex in the regulation of integrated function.

METHODS18 health pentobarbital-anaesthetized rabbits were divided evenly into 2 groups at random, bilateral sino-aortic denervation, intubated via right jugular vein to monitor CVP, left renal nerve separated and ending sectioned to record ERSNA, bilateral ureter intubated to collect urine, right femoral intubated to get blood sample. 15% of whole body blood volume of 0.9% and 1.8% sodium solution were injected via jugular vein 10 ml per minute respectively. The CVP, ERSNA, bilateral urine volume and coefficient of sodium excretion were measured before treated, during treated, one minute, five minutes and ten minutes after treated.

RESULTSVolume expansion by 0.9% and 1.8% sodium solution respectively resulted in the increase of CVP by 64.00% +/- 15.56% and 77.00% +/- 23.74%; the decrease of the frequency of ERSNA by 44.00% +/- 13.64% and 63.00% +/- 12.49%, the average burst time of ERSNA by 37.00% +/- 16.49% and 31.00% +/- 10.69%, the increase of average interval of ERSNA bursts by 60.00% +/- 18.38% and 68.00% +/- 27.04%; the increase of urine volume by 158.00% +/- 28.10% and 640.00% +/- 155.39% in left kidney, 192.00% +/- 32.26% and 1343.00% +/- 429.95% in the right; the increase of coefficient of sodium excretion by 132.00% +/- 35.23% and 376.00% +/- 121.72% in the left, 300.00% +/- 76.99% and 856.00% +/- 261.48% in the right.

CONCLUSIONVolume expansion by different solution stimulate the receptors of cardiopulmonary and regulate the water and sodium excretion of the kidney by the cardiac-renal reflex to modulate the stabilization of blood volume.

Animals ; Blood Volume ; drug effects ; physiology ; Central Venous Pressure ; Heart ; drug effects ; innervation ; Kidney ; drug effects ; innervation ; Rabbits ; Reflex ; Saline Solution, Hypertonic ; pharmacology

OBJECTIVESTo investigate the relationship between penile erection induced by L-arginine in paraventricular nucleus (PVN) and androgen.

METHODSTwenty-four mature male rabbits were randomly divided into three groups which were castrate, castrate with testosterone propionate (T) replacement and pseudo-operation. One month later, the highest intracavernous pressure (ICP) and nitric oxide synthase (NOS) of each PVN tissue were measured after infusing L-arginine into the PVN.

RESULTSThe mean ICPs of the highest values in castrate, castrate given T replacement and pseudo-operation groups were (22.640 +/- 4.747) mmHg, (38.146 +/- 4.907) mmHg and (39.991 +/- 3.068) mmHg, respectively. The mean value of NOS activity of each group were (0.807 +/- 0.188) U/mg.prot, (1.457 +/- 0.293) U/mg.prot and (1.528 +/- 0.204) U/mg.prot, respectively. The ICP and NOS activity in castrate were different statistically from T replacement and pseudo-operation group (both P < 0.01). T replacement group had no statistical difference from pseudo-operation group(P > 0.05).

CONCLUSIONSNitric oxide (NO) is one of the neurotransmitters in PVN particularly relevant for the control of penile erection. Penile erection induced by L-arginine in PVN depends on androgen.

Animals ; Arginine ; pharmacology ; Male ; Nitric Oxide ; physiology ; Paraventricular Hypothalamic Nucleus ; drug effects ; physiology ; Penile Erection ; drug effects ; Pressure ; Rabbits ; Testosterone ; blood ; pharmacology