Sleep-Related Changes in Cardiovascular Neural Regulation in Spontaneously Hypertensive Rats

Chen

et al. 2011

Circ J

Self Cite

Background: Cardiac angina is the hallmark of myocardial ischemia, but the role of the cardiac sensory nerve has received relatively little attention. Recently, both acid-sensing ion channel 3 (ASIC3) and capsaicin receptor (TRPV1) have been suggested as important mediators in sensing myocardial ischemia. However, studies comparing the physiological roles of ASIC3 and TRPV1 in the neuronal - cardiac sensing circuits in vivo are lacking. Methods and Results:Isoproterenol (1.5 mg/kg, intraperitoneally) was used to induce transient myocardial ischemia in Asic3 +/+ and Asic3 -/-mice and a radio-telemetry system was used for electrocardiography with mice in a conscious state. Isoproterenol-induced myocardial ischemia was first demonstrated with ST-segment depression and further confirmed by hypoxia-mediated chemical reactions in cardiac tissue. Mice lacking Asic3 showed prolonged duration of ST-segment depression compared with Asic3 +/+ mice (44.3±3.1 vs. 31.7±2.9 min; P<0.05). Although ischemia was transient, severe cardiac fibrosis was found in Asic3 -/-but not in Asic3 +/+ mice littermates. In contrast, isoproterenol-injected Trpv1 +/+ and Trpv1 -/-mice showed no difference in duration of ST-segment depression and, surprisingly, deletion of Trpv1 did not aggravate cardiac fibrosis.Conclusions: An isoproterenol-induced myocardial ischemia model mimicking clinical conditions of early cardiac angina was used to demonstrate that ASIC3 but not TRPV1 plays a protective role in sensing myocardial ischemia. (Circ J 2011; 75: 174 - 178)

Section: Telemetry Electrocardiography With Mice In a Conscious Statementioning

confidence: 99%

Acid-Sensing Ion Channel 3, But Not Capsaicin Receptor TRPV1, Plays a Protective Role in Isoproterenol-Induced Myocardial Ischemia in Mice

Chen

et al. 2011

Circ J

Self Cite

American Journal of Physiology-Heart and Circulatory Physiology

“…Several previous studies have examined spontaneous baroreflex control of HR during rapid, transient changes in blood pressure under various experimental and pathological conditions (1,3,11,13,18,21,25,32). However, whether the spontaneous baroreflex HR responses functionally translate into effective blood pressure regulation has often been uncertain, since the extent to which HR responses cause changes in CO can be variable.…”

Section: Discussionmentioning

confidence: 99%

“…Arterial baroreflex sensitivity (cardiac component) has often been assessed via techniques that analyze normally occurring spontaneous changes in blood pressure and the reciprocal changes in HR (3,12,21,32). This technique has been used as an index of cardiac baroreflex function in a number of species, including humans, and in many experimental and pathological conditions (1,3,11,13,18,21,25,32). Sinoaortic baroreflex denervation virtually abolishes baroreflex sensitivity assessed via this method, indicating that the spontaneous reciprocal changes in HR that occur as a result of changes in arterial pressure are indeed mediated by the baroreflex (1,19).…”

mentioning

confidence: 99%

Spontaneous baroreflex control of heart rate versus cardiac output: altered coupling in heart failure

Sala‐Mercado

Ichinose

Hammond

et al. 2008

Sala-Mercado JA, Ichinose M, Hammond RL, Coutsos M, Ichinose T, Pallante M, Iellamo F, O'Leary DS. Spontaneous baroreflex control of heart rate versus cardiac output: altered coupling in heart failure. Am J Physiol Heart Circ Physiol 294: H1304-H1309, 2008. First published January 11, 2008 doi:10.1152/ajpheart.01186.2007.-Dynamic cardiac baroreflex responses are frequently investigated by analyzing the spontaneous reciprocal changes in arterial pressure and heart rate (HR). However, whether the spontaneous baroreflex-induced changes in HR translate into changes in cardiac output (CO) is unknown. In addition, this linkage between changes in HR and changes in CO may be different in subjects with heart failure (HF). We examined these questions using conscious dogs before and after pacing-induced HF. Spontaneous baroreflex sensitivity in the control of HR and CO was evaluated as the slopes of the linear relationships between HR or CO and left ventricular systolic pressure (LVSP) during spontaneous sequences of greater or equal to three consecutive beats when HR or CO changed inversely versus pressure. Furthermore, the translation of baroreflex HR responses into CO responses (HR-CO translation) was examined by computing the overlap between HR and CO sequences. In normal resting conditions, 44.0 Ϯ 4.4% of HR sequences overlapped with CO sequences, suggesting that only around half of the baroreflex HR responses cause CO responses. In HF, HR-LVSP, CO-LVSP, and the HR-CO translation significantly decreased compared with the normal condition (Ϫ2.29 Ϯ 0.5 vs. Ϫ5.78 Ϯ 0.7 beats ⅐ min Ϫ1 ⅐ mmHg Ϫ1 ; Ϫ70.95 Ϯ 11.8 vs. Ϫ229.89 Ϯ 29.6 ml ⅐ min Ϫ1 ⅐ mmHg Ϫ1 ; and 19.66 Ϯ 4.9 vs. 44.0 Ϯ 4.4%, respectively). We conclude that spontaneous baroreflex HR responses do not always cause changes in CO. In addition, HF significantly decreases HR-LVSP, CO-LVSP, and HR-CO translation.arterial baroreflex sensitivity; parasympathetic activity; stroke volume THE ARTERIAL BAROREFLEX is the primary short-term regulator of systemic blood pressure via modulation of parasympathetic and sympathetic nerve activity (26). Changes in arterial blood pressure result in arterial baroreflex-mediated reciprocal changes in heart rate (HR) and total peripheral resistance. Arterial baroreflex sensitivity (cardiac component) has often been assessed via techniques that analyze normally occurring spontaneous changes in blood pressure and the reciprocal changes in HR (3,12,21,32). This technique has been used as an index of cardiac baroreflex function in a number of species, including humans, and in many experimental and pathological conditions (1,3,11,13,18,21,25,32). Sinoaortic baroreflex denervation virtually abolishes baroreflex sensitivity assessed via this method, indicating that the spontaneous reciprocal changes in HR that occur as a result of changes in arterial pressure are indeed mediated by the baroreflex (1, 19). However, changes in HR do not necessarily dictate changes in cardiac output (CO) because stroke volume (SV) may also vary, for example, with ...

Journal of Neurophysiology

“…We designed a special computer program in Pascal language (Borland Pascal 7.0, Borland) for bioelectric signals (Kuo et al 2004a(Kuo et al , 2004b(Kuo et al , 2010aKuo and Yang 2005). The digital signal processing of the bioelectric signals was similar to the procedures used in our previous studies (Kuo et al 2004a(Kuo et al , 2004b.…”

Section: Methodsmentioning

confidence: 99%

“…Sleep analysis was carried out according to our previously developed and semiautomatic computer procedure, which has been described in detail elsewhere (Kuo et al 2004a(Kuo et al , 2004bKuo and Yang 2005). The procedure discriminates the consciousness states into active waking, quiet sleep, and paradoxical sleep.…”

Section: Methodsmentioning

confidence: 99%

Voluntary and involuntary running in the rat show different patterns of theta rhythm, physical activity, and heart rate

Kuo

Yen³

et al. 2014

CC. Voluntary and involuntary running in the rat show different patterns of theta rhythm, physical activity, and heart rate. J Neurophysiol 111: 2061-2070, 2014. First published March 12, 2014 doi:10.1152/jn.00475.2013.-Involuntarily exercising rats undergo more physical and mental stress than voluntarily exercising rats; however, these findings still lack electrophysiological evidence. Many studies have reported that theta rhythm appears when there is mental stress and that it is affected by emotional status. Thus we hypothesized that the differences between voluntary and involuntary movement should also exist in the hippocampal theta rhythm. Using the wheel and treadmill exercise models as voluntary and involuntary exercise models, respectively, this study wirelessly recorded the hippocampal electroencephalogram, electrocardiogram, and three-dimensional accelerations of young male rats. Treadmill and wheel exercise produced different theta patterns in the rats before and during running. Even though the waking baselines for the two exercise types were recorded in different environments, there did not exist any significant difference after distinguishing the rats' sleep/wake status. When the same movement-related parameters are considered, the treadmill running group showed more changes in their theta frequency (4 -12 Hz), in their theta power between 9.5-12 Hz, and in their heart rate than the wheel running group. A positive correlation between the changes in high-frequency (9.5-12 Hz) theta power and heart rate was identified. Our results reveal various voluntary and involuntary changes in hippocampal theta rhythm as well as divergences in heart rate and high-frequency theta activity that may represent the effects of an additional emotional state or the sensory interaction during involuntary running by rats. wheel running; treadmill running; hippocampal theta rhythm; physical activity; heart rate