Five-striped palm squirrels (Funambulus pennantii), which are also known as northern palm squirrels, are rodents in the family Sciuridae. The natural geographic distribution of this squirrel species is Southeast Asia, including India, Pakistan, Nepal, Bangladesh, and Iran. Palm squirrels are an adaptable species that inhabit tropical and subtropical dry deciduous forests, mountain forests, scrublands, plantations, grasslands, arable lands, rural gardens, and urban areas.1–3 Palm squirrels are highly adaptable, and they reportedly are an invasive species in Australia, Israel, and the United Arab Emirates.4–7 Adult palm squirrels weigh between 135 and 200 g, and body length is 20 to 30 cm, half of which consists of the tail.4 These animals have been used for research, mainly in endocrinologic studies.8–14
Because of their fractious nature, squirrel-like species often need to be chemically immobilized or anesthetized to enable clinicians and researchers to perform examinations or diagnostic procedures.15–26 Inhalation anesthesia is commonly used to immobilize rodents because of rapid induction and recovery properties.22,24,27,28 Inhalation anesthesia is typically delivered to palm squirrels in a chamber or by use of a face mask, given that endotracheal intubation is technically challenging and therefore not routinely performed. However, use of a face mask for anesthesia increases the risk of exposure of veterinary personnel to waste gases, which is a major occupational health concern.29–31 Therefore, alternative anesthetic regimens (eg, injectable anesthetic drugs for induction and maintenance of anesthesia) are desired when inhalation anesthesia cannot be performed or to reduce exposure to waste gas.16,17,19,32
A suitable injectable anesthetic combination should involve short-acting anesthetic drugs with a wide safety margin that preferably are reversible.16,17,19,28,32–34 Regimens involving SC or IM injection of ketamine and α2-adrenoceptor agonist combinations are routinely used as a practical method of anesthesia for rodents, especially when inhalation anesthesia equipment is not readily available (eg, field settings) or when an animal cannot readily be intubated (eg, palm squirrels).16,17,19,27,28,32,34 Dexmedetomidine is an α2-adrenoceptor agonist that is reversible and provides analgesia, sedation, and muscle relaxation.28 Ketamine is a dissociative, centrally acting antagonist of the N-methyl-d-aspartate receptor that also provides analgesia.28 Midazolam, a benzodiazepine, is reversible and commonly used with minimal adverse effects to sedate rodents.28 Coadministration of dexmedetomidine and midazolam to rats results in a dose-related analgesic effect and rapid induction of sedation.35 In black-tailed prairie dogs (Cynomys ludovicianus), another member of the Sciuridae, anesthesia with DKM appears to be an effective alternative to isoflurane for brief procedures that require rapid induction and analgesia.17 For this reason, the DKM combination was chosen for use in the study reported here.
Reports on the use of injectable anesthetics in palm squirrels are sparse in the literature. Five-striped palm squirrels were immobilized for intracardiac collection of blood samples by anesthetic induction with isoflurane followed by IM administration of a high dose of ketamine (100 to 150 mg/kg).4 To the authors’ knowledge, data on clinically appropriate injectable anesthetic regimens for use in five-striped palm squirrels have not been published. The objective of the study reported here was to determine the physiologic effects, including assessment of anesthetic variables and vital signs, after administration of a DKM combination in five-striped palm squirrels during a period suitable for most testing and therapeutic procedures.16,19,32 Our hypothesis was that the DKM combination would provide safe and effective anesthesia in palm squirrels.
Supported by the Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University.
The authors declare that there were no conflicts of interest.
The authors thank Dr. Roi Lapid, Dr. Avital Paz, Dr. Nili Avni-Magen, Nufar Eshkar Carmel, and Ariella Bary for technical assistance.
Oxygen saturation as measured by pulse oximetry
Dexdomitor, Orion Corp, Espoo, Finland.
Ketaset, Hospira, Lake Forest, Ill.
Hospira, Lake Forest, Ill.
BD Ultra-Fine II, Becton, Dickinson and Co, Franklin Lakes, NJ.
Antisedan, Orion Corp, Espoo, Finland.
Flumazenil, Hikma Farmaceutica, Terrugem, Portugal.
Model 811-B Doppler flow detector, Parks Medical Electronics, Las Vegas, Nev.
BCI 3301, Smiths Medical PM Inc, Waukesha, Wis.
Nonin PalmSat 2500, Nonin Medical, Plymouth, Minn.
R package, version 3.1-121, R Foundation for Statistical Computing, Vienna, Austria.
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