Cardiovascular response caused by intracerebroventricular microinjection of interleukin-2 / 中国应用生理学杂志

<p><b>AIM</b>To investigate the cardiovascular response caused by intracerebroventricular (ICV) microinjection of interleukin-2 (IL-2) and explore the underlying mechanism.</p><p><b>METHODS</b>Male Sprague-Dawley rats were anesthetized with intraperitoneal urethane( 1.2 g/ kg). The changes of mean arterial blood pressure (MAP) and heart rate (HR) were observed during ICV microinjection of IL-2 with or without pretreatment of naloxone or atropine or phentolamine.</p><p><b>RESULTS</b>There were no significant effects on cardiovascular response after ICV injection of IL-2 at 500 IU/3 microl and 1 000 IU/3 microl, but IL-2 at 1 500 IU/3 microl could elevate MAP and HR. The responses of MAP and HR reached their maximum levels at 10 min (MAP: 10 +/- 1.8 mmHg, HR: 25 +/- 2 b/min, P < 0.05) after the injection and lasted 15 or 10 minutes respectively. Pretreatment with naloxone (10 microg/10 microl) or atropine (1.5 microg/10 microl) could block the cardiovascular response of ICV injection of IL-2. Pretreatment with phentolamine (10 microg/10 microl) failed to block the cardiovascular responses by IL-2.</p><p><b>CONCLUSION</b>ICV microinjection of interleukin-2 (IL-2) can elevate the MAP and HR, which may be mediated by central opioid and cholinergic system. The alpha-adrenergic system may be not involved in the cardiovascular response of IL-2.</p>

The regulation of area postrema in cardiovascular function in rabbit / 中国应用生理学杂志

<p><b>AIM</b>To determine the role of area postrema (AP) of rabbit in the regulation of cardiovascular function.</p><p><b>METHODS</b>The rabbits were anesthetized with intravenous injection of 10% urethane and 1% chloralose, and were artificially ventilated. The changes of mean arterial pressure (MAP) and heart rate (HR) were observed when AP was electrically stimulated with different frequency (10 Hz -80 Hz) and after chemical lesion of CVLM or RVLM, respectively.</p><p><b>RESULTS</b>Electrical stimulation of AP with low frequency (10 Hz, 20 Hz) decreased MAP and HR. Stimulation with high frequency(60 Hz, 80 Hz) increased MAP but decreased HR. The changes in MAP and HR were significantly lower (P < 0.01) after CVLM was destroyed when electrical stimulation of AP with 20 Hz, and both changes of MAP and HR were disappeared (P < 0.01) after RVLM was destroyed when electrical stimulation with 20 and 80 Hz.</p><p><b>CONCLUSION</b>Electrical stimulation of AP with low frequency decreases MAP and HR, stimulation with high frequency induces an increase in MAP and decreases in HR. The former is probably related to excitation of CVLM, the cardiovascular effects induced by different frequency of electrical stimulation are all resulted from the activation of RVLM.</p>

Role of area postrema of medulla in regulation of rat cardiovascular activity / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To explore the role of area postrema (AP) of medulla in control of cardiovascular functions in rat.</p><p><b>METHODS</b>(1) Sprague Dawley rats were anaesthetized with urethane and pentobarbital and the AP was stimulated by electrical stimulus with intensity of 0.1 mA and frequencies ranged 10 approximate, equals 80 Hz. (2) Excitatory amino acid L-glutamate (L- Glu, 0.1 approximate, equals 0.5 mol/L) was microinjected into AP in urethane anaesthetized rats and the changes of mean arterial pressure (MAP) and heart rate (HR) were recorded.</p><p><b>RESULT</b>(1) When the frequencies of 10 Hz, 20 Hz and 40 Hz were used, the electrical stimulation of AP caused decrease of MAP and HR (P<0.001),while the electrical stimulation with the frequencies of 60 Hz and 80 Hz caused an increase of MAP (P<0.05) but a decrease of HR (P<0.001). (2) Microinjection of L-Glu at 0.1 mol/L had no effect on MAP and HR (P>0.05), but it decreased MAP and HR at 0.15 mol/L (P<0.001, P<0.05). The MAP was increased (P<0.001) but HR (P<0.05) was decreased at the concentrations of 0.2 mol/L and 0.5 mol/L, respectively.</p><p><b>CONCLUSION</b>Alterations of MAP and HR induced by electrical or chemical stimulation on AP of medulla are related to the frequency of electrical stimulation or concentration of L-Glu.</p>

Interaction between opioid receptor and adrenoceptor signaling in ischemia reperfusion of the isolated rat heart / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the interaction between opioid receptor (OR) stimulation and adrenergic receptor (AR) stimulation in the isolated ischaemia/reperfusion (I-R) rat heart.</p><p><b>METHODS</b>Male Sprague-Dawley rats were used for Langendoff isolated heart perfusion. Myocardial ischemia for 20 min was followed by 30 min of reperfusion, during which the kappa-OR agonist U50488h and beta(1)-AR agonist norepinephrine (NE) were administered.</p><p><b>RESULTS</b>(1) 50488h antagonized the effect of NE in rising left ventricular systolic pressure (LVSP) in the early phase of myocardial ischemia at 10, 20, 30 min of reperfusion. (2) Arrhythmia scores in the I-R+NE+U50488h group were markedly lower than those in the I-R group during the 10 - 20 min reperfusion period. No significant differences in arrhythmia scores were found in either I-R+U50488h or I-R+NE group when compared with I-R group. (3) Compared with the I-R group, U50488h alone or plus NE decreased reperfusion heart rates after myocardial ischemia while NE alone showed no effect.</p><p><b>CONCLUSION</b>It is suggested that the interaction in the signaling pathway between kappa-OR and beta(1)-AR occurred during myocardial I-R of rat heart.</p>