ABSTRACT
Objective To verify the feasibility of a rat model of acute hypertension, and to observe the imaging findings at 7.0T MR scanner of the model.Methods In experimental group, the rats were scanned at 7.0T Bruker MR scanner when phenylephrine was injected continuously to evoke an acute hypertension state.The real time blood pressure was monitored through a femoral arterial catheter connected to a pressure transducer.The control group was infused with saline.T2WI, DWI and T1 mapping were performed in the two rat groups.ADC maps and T1 maps were acquired after image post-processing, and a voxel wise analysis and a ROI analysis were applied.The brain morphology change was evaluated by HE staining.The blood-brain barrier permeability was evaluated by Evans blue staining.Results The T2 images and DWI images of the experiment group showed no abnormal signal intensity changes observed by naked eyes.But ROI analysis of the ADC maps showed that the brain ADC values of the experiment group was higher than the control group (t=3.291,P0.05).The blue dye region was only performed in the experimental group,the results of HE staining corresponded with vasogenic brain edema.Conclusion Continuous infusing of phenylephrine hydrochloride can induce a rat model of acute hypertension.Vasogenic edema and blood-brain barrier permeability change can be observed in the rat model, and the imaging distribution of vasogenic edema can be detected by MRI.
ABSTRACT
Objectives To explore the effects and mechanism of acupuncture treatment in emergent of acute hypertension by studying the acupuncture treatment on acute hypertension rats. Method The acute hypertension rat model was made by injecting adrenalin into the abdomen. After probing specific points, NO, ET-1, angiotensin and rennin levels were tested. Results Acupunctured for 30 minutes, the experimental group's diastolic pressure dropped and NO level rose, and these changes were statistically significant regarding those of the medicine control group. After the acupuncture treatment, the rennin level of the medicine control group and the experimental group were statistically different with the control group, but no significant difference was found between the medicine control group and the experimental group. Conclusion Probing Quechi, Taichong, Sanyinjiao and Neiguan may lead to the improved performance of the vessel endoderm, the rise of NO level and the decrease of angiotensin content, and consequently reduce the blood pressure of acute hypertension rats.
ABSTRACT
This study was undertaken to determine the cardiovascular response to the spinal cord trauma in cats and to determine the autonomic mechnisms involved. The electrocardiogram and arterial blood pressure were recorded in anesthetized cats after the spinal cord trauma of 500 gm-cm at T4-T6 levels. 1. Acute spinal cord trauma caused a wide variety of severe cardiac arrhythmias and acute hypertension. 2. The increase of blood pressure could be prevented by intravenous phenoxybenzamine, and alpha adrenergic blocking agent. The pressor response was mediated by the alpha adrenergic receptor sites of the peripheral nervous system. 3. Tachycardia was occurred by the administration of atropine and bilateral vagotomy before trauma without affecting pressor response. 4. The arrhythmias could be eliminated by the combined administration of propranolol and atropine, but not prevented by the administration of either propranolol or atropine without affecting pressor response. These results suggest that the arrhythmias might be a response of hyperactivity of both sympathetic and parasympathetic divisions of the autonomic nervous system.