Cephalopods are important in biologic and biomedical research, yet relatively little objective information is available toguide researchers and veterinarians regarding the best methods for anesthetizing these animals for various experimentalprocedures. Recent studies demonstrate that ethyl alcohol and magnesium chloride are effective at depressing efferent andafferent neural signals in some tropical cephalopod species when measured via the pallial nerve. Here we used similar methodsto test 2 temperate species (Octopus bimaculoides and Sepia officinalis) and demonstrate that (1) ethyl alcohol and magnesium chloride were effective at reversibly depressing evoked activity in the pallial nerve, (2) ethyl alcohol generally had shorter induction and recovery times compared with magnesium chloride, (3) both agents were associated with a latency between the behavioral and neural effects, and it was longer with magnesium chloride, and (4) senescent animals generally had longer induction or recovery times than young animals. Both agents successfully anesthetized both life stages; however, our data show that assessing anesthesia based solely on behavior may lead to premature commencement of invasive procedures. We conclude that temperate cephalopods can be humanely, effectively, and completely anesthetized by using these 2 agents and that the loss of neural signal we show here is consistent with true anesthesia and not merely paralysis. This relatively simple, nondestructive nerve recording technique can be applied to the study of other prospective anesthetic agents in cephalopods.

Background: There is little information on the correlation between equine recurrent uveitis (ERU) and leptospiral infection status as it relates to ocular examination findings and testing recommendations. Objective: To evaluate the role of leptospiral testing in horses with ERU by correlating results to signalment, clinical findings and visual outcome. Study design: Retrospective case series. Methods: Records of horses presenting for ERU at NC State University Veterinary Health Complex (NCSU-VHC) between 2014 and 2019 were reviewed. Signalment, initial visual status, ocular examination findings, treatments and visual outcome were collected. Serum and aqueous humour (AH) leptospiral titres were assessed for six different leptospirosis serovars and polymerase chain reaction (PCR) testing. Goldmann-Whitmer (C) values were calculated. Results: Records of 63 horses and 78 eyes with ERU were evaluated. Horses with a positive aqueous humour PCR were significantly younger in age (mean 9.25 AE 1.14) than PCR negative horses (mean 13.3 AE 0.95) (p = 0.01). A positive aqueous humour titre of any serotype was significantly correlated to blindness at presentation (p = 0.04). A positive serum titre was significantly correlated to presence of ocular posterior segment disease (p = 0.01). Positivity to L. bratislava in the serum correlated to posterior segment disease (p = 0.04) and AH positivity correlated to blindness at presentation (p = 0.002). Main limitations: Limitations of this study include that it is a retrospective and information gathered relies on data included within medical records. Conclusions: Positive leptospiral testing results were associated with younger horses and ocular posterior segment clinical disease. Horses with aqueous humour titres to any leptospiral serotype, especially L. bratislava serovar, were correlated to poor prognosis for vision. Clinical relevance• To educate owners and veterinarians about the correlation between ERU clinical signs and leptospiral infection status.• To help owners and veterinarians understand the role of leptospiral testing and ERU outcome/prognosis.• To make recommendations about testing for leptospirosis as it relates to ERU, the leading cause of blindness in horses.

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