Time-Dependent Change in Baroreflex Control Capacity of Arterial Pressure by Pentobarbital Anesthesia in Rabbits.

Abstract

Abstract:The present study is designed to investigate the time-dependent effect of pentobarbital anesthesia on the baroreflex arterial pressure (AP) control system in rabbits. The overall AP control capacity of the baroreflex system was assessed with mean arterial pressure (MAP) responses to the rapid mild hemorrhage (2 ml/kg body weight) and an overall open-loop gain (G) of the system. The G value was determined by means of the following formula: G=∆AP I /∆AP S -1, where ∆AP I is an immediate MAP fall and ∆AP S a steady-state fall after the rapid hemorrhage. Prior to the experiment, two catheters for AP measurement and hemorrhage were chronically in-dwelt in the aortic arch via the left subclavian and left common carotid arteries, respectively. Control mean arterial pressure averaged for 30 sec before the rapid hemorrhage (CMAP), ∆AP I and ∆AP S significantly increased and reached the maximal value at 14 min (CAMP: p<0.01) and 28 min (∆AP I : p<0.01 and ∆AP S : p<0.01) after the intravenous injection of sodium pentobarbital in a 25.0 mg/kg dose, respectively. These values gradually decreased in the course of time and tended to recover to near the preanesthetic level at 77-98 min after the anesthesia. The G value significantly decreased from 7.3 in the conscious state to 1.5 at 28 min after the anesthesia (p<0.001), gradually increased with lapse of time and recovered to near the preanesthetic level at 77-98 min after the anesthesia. No significant difference in G was observed between in the conscious and anesthetized states beyond 70 min after the anesthesia (p>0.05). These findings suggest that pentobarbital sodium exerts a timedependent inhibitory effect on the baroreflex system but does not significantly affect the overall AP control capacity of the baroreflex system itself at least 70 min after the intravenous administration at a dose of 25.0 mg/kg.

Regulation of Blood Pressure and Salt Homeostasis by Endothelin

“…Part of the problem relates to the presence of anesthesia as well as the type of anesthesia; these can profoundly influence baroreflex function (45, 354, 695). In addition, salt balance and volume status can modify baroreflexes (551); these are not typically well controlled.…”

Electrical stimulation of the aortic depressor nerve in conscious rats overcomes the attenuation of the baroreflex in chronic heart failure

“…It is of interest to note that in the current study, the ADN stimulation was carried out 24 h after the surgical procedures. Because it is well documented that pentobarbital sodium affects the baroreflex control of the autonomic nervous system in rats (37), as well as rabbits (22), a residual effect of anesthesia upon the baroreflex cannot be totally ruled out in the current study. However, the electrical activation of the aortic baroreflex 24 h after recovery from pentobarbital sodium anesthesia was effective to overcome both the attenuation of parasympathetic function and the sympathetic overdrive characteristic of CHF.…”

Antihypertensive effects of edible brown seaweeds in rats

“…The aqueous extract of all the three types of brown seaweeds showed various degrees of blood pressure reduction effects in both anaesthetised SHR and WKY rats. Anaesthesia was done using pentobarbitone sodium (50 mg/kg) as it is widely used in veterinary and preclinical medicine (Katsuda et al, 2000). In addition, rats that was anaesthetised with pentobarbitone sodium were not susceptible to external disturbances that may lead to fluctuations in the blood pressure, and therefore, a stable experimental condition can be established for the study (Katsuda et al, 2000).…”

“…Anaesthesia was done using pentobarbitone sodium (50 mg/kg) as it is widely used in veterinary and preclinical medicine (Katsuda et al, 2000). In addition, rats that was anaesthetised with pentobarbitone sodium were not susceptible to external disturbances that may lead to fluctuations in the blood pressure, and therefore, a stable experimental condition can be established for the study (Katsuda et al, 2000). In this study, the MAP value is used as the blood pressure indicator, as it is the average effective pressure that considers both the SBP and DBP that drives blood through the systemic organs (Mohrman, 1997).…”