Ketamine-HCI as a Suitable Anesthetic for Endocrine, Metabolic, and Cardiovascular Studies in Macaca fascicularis Monkeys

Abstract

Ketamine-HCl has been reported, depending on experimental conditions and dosage given, to have significant cardiovascular and endocrine effects in some species. However, previous studies in primates have inadequately distinguished between animal handling and ketamine effects. We, therefore, examined the effects of various doses of ketamine (0, 5 , 10, 15, and 20 mg/kg) on mean arterial blood pressure and on plasma insulin, glucose, and cortisol concentrations in 10 chronically cannulated Macaca fascicularis monkeys which had been acclimated to restraining chairs. Each monkey received three different doses of ketamine according to a balanced incomplete block design. Ketamine anesthesia produced no significant changes in plasma insulin, glucose, or cortisol concentrations nor did it affect mean arterial blood pressure. In addition, the effects of ketamine-HC1 on endocrine responses to insulin-induced hypoglycemia were examined in four animals according to a cross-over design. These animals also had chronically maintained cannulas and had been acclimated to restraining chairs. Plasma glucose concentrations, as well as plasma ACTH, growth hormone, and cortisol responses in ketamine-anesthetized animals receiving an insulin challenge were no different from those in unanesthetized control animals. Thus, our studies indicate that ketamine-HCl does not perturb these particular hormonal systems in M. fuscicularis monkeys. 389

Pharmacologic restoration of the early insulin response in pre-diabetic monkeys controls mealtime glucose excursions without peripheral hyperinsulinaemia

“…Ketamine-induced sedation has been shown to modestly suppress plasma glucose and insulin concentrations in baboons [15] possibly accounting for the relatively low fasting plasma glucose concentrations observed in this study. However, a stable and consistent plane of anesthesia is achievable by the protocol used [16] and any differences between groups treated with different agents should be attributable to the compounds per se. The doses of compound used were chosen based on preliminary range-finding studies which indicated that 20 mg/kg of nateglinide would elicit an increment of plasma IRI equivalent to that induced by 0.1 mg/kg of repaglinide.…”

Research Techniques for the Squirrel Monkey (Saimiri sp.)

“…General anesthesia with ether can cause growth hormone release in squirrel monkeys (Brown et al 1971a). Ketamine anesthesia has been postulated to cause changes in glucose tolerance test results in other nonhuman primates (Streett and Jonas 1982); however, this belief has been disputed by others (Brady and Koritnik 1985;Castro et al 1981;Kemnitz and Kraemer 1982). The ultrashort-acting barbiturate anesthetic sodium thiopental can cause premature ventricular contractions in squirrel monkeys (Wolf et al 1969).…”

Circadian cortisol secretion and circadian adrenal responses to ACTH are maintained in dexamethasone suppressed capuchin monkeys (Cebus apella)

“…Afterwards inhalatory anesthesia with halothane (0.5-1% in 100% oxygen) was initiated and maintained during the experiment. Ketamine is reported to have limited effects upon plasma cortisol concentration in capuchin monkeys familiarized with sampling procedures [Lahoz et al, 2007] and in trained cynomolgus [Macaca fascicularis ;Castro et al, 1981;Malaivijitnond et al, 1998] and rhesus monkeys [Bentson et al, 2003;Elvidge et al, 1976;Fuller et al, 1984]. However, increases in plasma cortisol after ketamine have been reported in capuchin monkeys not familiarized with restraint [Lahoz et al, 2007], and in untrained rhesus monkeys [Macaca mulatta; Elvidge et al, 1976] and baboons [Papio cynocephalus/anubis; Bentson et al, 2003].…”