Dosage selection and effect evaluation of sodium pentobarbital in tree shrew anesthesia

To achieve surgical anesthesia in animal experimentation, it is important to select the appropriate anesthetic dose. However, few studies have investigated the reasonable anesthetic dose in tree shrew (Tupaia belangeri). The aim of the study was to review the literature to determine the most commonly used anesthetic dose in tree shrew and to calculate the reasonable equivalent dose between tree shrew and rat based on the body surface area conversion. Two groups of 10 adult tree shrews each were anesthetized with 1% sodium pentobarbital through intraperitoneal injection separately at doses of 62 mg/kg (equivalent dose) and 40 mg/kg (reported dose). Anesthetic depth and times were assessed in addition to vital signs. The results showed that the dosage was quite different across studies, ranging from 15 mg/kg to 80 mg/kg, with 40 mg/kg being the most frequently reported dose. However, the group of tree shrews anesthetized with the commonly reported dose were unable to meet the requirements of surgery. In contrast, the equivalent dose (62 mg/kg, intraperitoneal injection with sodium pentobarbital) calculated by body surface area conversion could achieve an anesthetic time of 44.28 ± 3.95 min with no serious or fatal effects. During anesthetic monitoring, we found that sodium pentobarbital had an inhibitory effect on the blood pressure, pulse rate, respiratory rate and rectal temperature in tree shrews, especially on the respiratory rate. Thus, our study indicated that the use of the equivalent dose of sodium pentobarbital was effective in anesthetizing tree shrews.