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Conscious Rabbits (conscious + rabbits)

Distribution by Scientific Domains

Medical Sciences	60%

Selected Abstracts

Effects and probable mechanisms of electroacupuncture at the Zusanli point on upper gastrointestinal motility in rabbits

JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 10 2007
Wei-Xin Niu
Abstract Background and Aim:, The purposes of this study were to investigate the regulative effect of acupuncture on gastrointestinal motility in rabbits and to explore the probable mechanism of electroacupuncture. Methods:, The experiment was performed on 30 rabbits implanted with three pairs of electrodes, which were equally divided into three groups: the control group, the Zusanli group, and the non-acupuncture point group. The gastrointestinal myoelectrical activity of each conscious rabbit was recorded when acupuncture was applied. Motilin in plasma, cholecystokinin (CCK) in serum, the activity of acetylcholine esterase, nitric oxide synthase (NOS), and the vesicle of nerve endings in the stomach tissue and jejunum were investigated. Results:, It was found that electroacupuncture did not exert much influence on the slow wave of gastrointestinal myoelectrical activity, but significantly increased the number and amplitude of spikes. In the Zusanli group, the concentration of motilin and CCK was much higher at the post-acupuncture stage than at the pre-acupuncture stage. Electroacupuncture significantly enhanced the activity of acetylcholine esterase. Moreover, we found out that in the Zusanli group, the number of vesicles without granula was significantly fewer than in the control group. The activity of NOS was less in the Zusanli group than in the control group. Conclusions:, Acupuncture may enhance the gastrointestinal myoelectrical activity of conscious rabbits. The cholinergic nerve, nitric oxide, motilin, and CCK may contribute to acupuncture mechanisms. [source]

Release of ATP in the central nervous system during systemic inflammation: real-time measurement in the hypothalamus of conscious rabbits

THE JOURNAL OF PHYSIOLOGY, Issue 1 2007
Alexander V. Gourine
Receptors for extracellular ATP (both ionotropic and metabotropic) are widely expressed in the CNS both in neurones and glia. ATP can modulate neuronal activity in many parts of the brain and contributes to the central nervous control of several physiological functions. Here we show that during the systemic inflammatory response the extracellular concentrations of ATP increase in the anterior hypothalamus and this has a profound effect on the development of the thermoregulatory febrile response. In conscious rabbits we measured ATP release in real time with novel amperometric biosensors and monitored a marked increase in the concentration of ATP (4.0 ± 0.7 ,m) in the anterior hypothalamus in response to intravenous injection of bacterial endotoxin , lipopolysaccharide (LPS). No ATP release was observed in the posterior hypothalamus. The release of ATP coincided with the development of the initial phase of the febrile response, starting 18 ± 2 min and reaching its peak 45 ± 2 min after LPS injection. Application of the ATP receptor antagonists pyridoxal-5,-phosphate-6-azophenyl-2,,4,-disulphonic acid, Brilliant Blue G or periodate oxidized ATP dialdehyde to the site of ATP release in the anterior hypothalamus markedly augmented and prolonged the febrile response. These data indicate that during the development of the systemic inflammation, ATP is released in the anterior hypothalamus to limit the magnitude and duration of fever. This release may also have a profound effect on the hypothalamic control of other physiological functions in which ATP and related purines have been implicated to play modulatory roles, such as food intake, hormone secretion, cardiovascular activity and sleep. [source]

Pharmacological delayed preconditioning against ischaemia-induced ventricular arrhythmias: effect of an adenosine A1 -receptor agonist

BRITISH JOURNAL OF PHARMACOLOGY, Issue 7 2001
Renaud Tissier
The goal of this study was to investigate the effects of the delayed pharmacological preconditioning produced by an adenosine A1 -receptor agonist (A1 -DPC) against ventricular arrhythmias induced by ischaemia and reperfusion, compared to those of ischaemia-induced delayed preconditioning (I-DPC). Eighty-nine instrumented conscious rabbits underwent a 2 consecutive days protocol. On day 1, rabbits were randomly divided into four groups: ,Control' (saline, i.v.), ,I-DPC' (six 4-min coronary artery occlusion/4-min reperfusion cycles), ,A1 -DPC100' (N6 -cyclopentyladenosine, 100 ,g kg,1, i.v.), and ,A1 -DPC400' (N6 -cyclopentyladenosine, 400 ,g kg,1, i.v.). On day 2, i.e., 24 h later, the incidence and severity of ventricular arrhythmias during a 30-min coronary artery occlusion and subsequent reperfusion were analysed in all animals, using an arrhythmia score. I-DPC, A1 -DPC100 and A1 -DPC400 significantly reduced the infarct size (34±5, 42±3 and 43±7% of the area at risk, respectively) as compared to Control (55±3% of the area at risk). During both ischaemia and reperfusion, neither the incidence nor the severity of ventricular arrhythmias were altered by A1 -DPC100, A1 -DPC400 or I-DPC as compared to Control. Thus, despite reduction of infarct size induced by delayed preconditioning, A1 -DPC as well as I-DPC failed to exert any anti-arrhythmic effect in the conscious rabbit model of ischaemia-reperfusion. British Journal of Pharmacology (2001) 134, 1532,1538; doi:10.1038/sj.bjp.0704407 [source]

Renal And Cardiac Sympathetic Baroreflexes In Hypertensive Rabbits

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 12 2001
Geoffrey A Head
SUMMARY 1. The purpose of the present study was to assess the changes to renal sympathetic nerve activity (RSNA) baroreflexes during the development of hypertension after renal clipping in conscious rabbits. 2. Rabbits were fitted with a clip on the right renal artery or underwent a sham operation under halothane anaesthesia. A recording electrode was implanted on the left renal nerve 1 week before the experiment, 3 or 6 weeks after the initial operation. During the experiment, drug-induced ramp rises and falls in mean arterial pressure (MAP) were used to produce RSNA and heart rate (HR) baroreflex curves. The RSNA for each experiment was calibrated against maximum RSNA evoked by stimulation of baroreceptor-independent trigeminal afferents. 3. Mean arterial pressure was 20 and 36% higher 3 and 6 weeks after clip implantation, respectively. Renal sympathetic nerve activity baroreflex curves were reset rightwards accordingly, but the shape of the RSNA curves was differentially affected. 4. At both hypertensive periods, MAP,HR baroreflex gain was markedly reduced due to a reduction in curvature. The HR baroreflex range was increased. The RSNA baroreflex gain was reduced at 3 weeks, which was due to a 35% lower RSNA baroreflex range, but was similar to sham animals at 6 weeks. 5. The results show that, in established two kidney, one clip hypertension in rabbits, the sympathetic baroreflex is relatively well preserved but sensitivity of cardiac baroreflexes is attenuated. Therefore, the short-term inhibition of RSNA baroreflexes is not related to the level of blood pressure or the development of secondary changes, such as cardiac or vascular hypertrophy, but may be related to circulating angiotensin, which is known to increase at this time. [source]