Comparison of intramuscular administration of alfaxalone-ketamine-dexmedetomidine and alfaxalone-butorphanol-midazolam in naked mole-rats (Heterocephalus glaber)

Abstract

OBJECTIVE To compare anesthetic effects of alfaxalone-ketamine-dexmedetomidine (AKD) and alfaxalone-butorphanol-midazolam (ABM) in naked mole-rats (Heterocephalus glaber). ANIMALS 20 naked mole-rats. PROCEDURES Naked mole-rats received AKD (alfaxalone, 2 mg/kg; ketamine, 20 mg/kg; and dexmedetomidine, 0.02 mg/kg; n = 10) or ABM (alfaxalone, 2 mg/kg; butorphanol, 2 mg/kg; and midazolam, 1 mg/kg; 9) IM; 1 animal was removed from the study. Atipamezole (I mg/kg) and flumazenil (0.1 mg/kg) were administered 40 minutes after anesthetic induction (defined as loss of the righting reflex) with AKD and ABM, respectively. Heart rate, respiratory rate, oxygen saturation, and reflexes were recorded every 5 minutes. RESULTS The ABM group had significantly longer median times for induction and recovery than the AKD group. Administration of ABM resulted in significantly lower respiratory rates than administration of AKD from time of anesthetic induction to 10 minutes after induction. Respiratory rate significantly decreased in the AKD group from I0 minutes after induction through the end of the anesthetic period but did not change over time in the ABM group. Males had higher respiratory rates in both groups. Loss of the righting reflex was still evident 40 minutes after induction in both groups. In the AKD group, all tested reflexes were absent from I0 to 40 minutes after induction; the ABM group had variable reflexes that recovered within individual animals over time. CONCLUSIONS AND CLINICAL RELEVANCE Both AKD and ABM provided effective immobilization in naked mole-rats, but AKD appeared to provide more consistent and deeper anesthesia, compared with administration of ABM.

Anesthetic effects of alfaxalone-ketamine-midazolam and alfaxalone-ketamine-dexmedetomidine administered intramuscularly in black-tailed prairie dogs (Cynomys ludovicianus)

“…The smooth induction quality observed in this study is similar to what has been observed in naked mole rats (Heterocephalus glaber) and fivestriped palm squirrels (Funambulus pennantii) receiving various combinations of alfaxalone with ketamine, dexmedetomidine, butorphanol, or midazolam. [12][13][14][15] In contrast, chinchillas (Chinchilla lanigera) anesthetized with alfaxalone-butorphanol experienced rolling, twitching, and tremors throughout induction of anesthesia, mice given alfaxalone or alfaxalonexylazine experienced erratic jumping and limb jerking during induction, and rats frequently twitched during recovery when given alfaxalone intraperitoneally. 13,18,21,32 This could perhaps be attributed to the use of significantly higher alfaxalone doses in rats and mice; however, the chinchillas in the aforementioned study received comparable alfaxalone doses to the dose evaluated in this study.…”

“…The recovery quality for both studied protocols was smooth with no obvious adverse events, similar to the observed recovery quality of naked mole rats after receiving alfaxalone based anesthetic protocols. 14,15 Prior studies 18,21,32 evaluating alfaxalone in rats and mice or alfaxalone combined with xylazine in mice observed erratic jumping behavior, intense facial scratching, limb jerking, and facial twitching during the recovery period. Five-striped palm squirrels experienced twitching, tail lifting, and vocalization throughout recovery after receiving Body temperature was significantly different between protocols (P < .001), over time (P < .001) (Figure 4), but not with weight (P = .55).…”

“…The study population was also limited with a total of 9 animals, and although expanding the study population would give a more comprehensive observation of the effects of AKM and AKD on black-tailed prairie dogs, this number of subject animals was also used in other anesthesia studies in a variety of species. 14,18,[40][41][42] Additionally, the physiologic parameters measured in the current study could have been expanded for a more comprehensive evaluation of cardiovascular and respiratory effects of AKM and AKD. As noted above, the pulse oximetry readings obtained in the current study were difficult to interpret due to the degree of variability, so blood gas analysis could have provided a valuable measure of ventilation and oxygenation in addition to respiratory rate.…”

“…It has been increasingly investigated as an injectable anesthetic option in a variety of rodent species, particularly via subcutaneous, intramuscular, or intraperitoneal routes. [12][13][14][15][16][17][18][19][20][21][22] Alfaxalone is a neuroactive steroid that produces nonreversible, nonanalgesic anesthesia and muscle relaxation through interaction with the gammaaminobutyric acid (GABA) receptors within the CNS. 22 When used in guinea pigs (Cavia porcellus), rats (Rattus norvegicus), and mice (Mus musculus), alfaxalone as a single agent intraperitoneally, subcutaneously, or intramuscularly, it produces inconsistent planes of anesthesia, generally not reaching a surgical plane of anesthesia regardless of dosage.…”

“…[16][17][18][19][20] The combination of alfaxalone with a dissociative agent or alpha-2 agonist has been documented to provide a deeper, more consistent plane of anesthesia in the rodent species evaluated thus far. [12][13][14][15][16]20,21 Injectable anesthetic protocols that include alfaxalone have not been evaluated in black-tailed prairie dogs previously.…”