Have You Heard? Can pheromones ease surgical stress? (transcript)

A commercially available synthetic canine pheromone is marketed to produce a calming effect in dogs encountering stressful situations such as kenneling, separation anxiety, and fear. This pheromone originates from intermammary sebaceous secretions of lactating bitches, but the precise mechanism of action is not known.

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Researchers in Spain aimed to evaluate the effect of exposure to this pheromone on the perioperative stress response in dogs and evaluated a variety of indicators representing the neuroendocrine, immune, and acute-phase stress responses. They assessed alterations in behavior—specifically decreases in alertness and visual exploration. They also measured other indicators of stress, inflammation, and pain, including salivary cortisol concentration, white blood cell count, and serum glucose and prolactin concentrations.

Forty-six young, healthy dogs having spent at least 20 days in a shelter and scheduled for routine ovariohysterectomy or orchiectomy were included in this study. Dogs showing overt signs of aggression or classic displays of pacing, circling, or tail-chasing were excluded. With an even distribution of age, weight, and sex, they were randomly divided into two groups—one exposed to the pheromone solution before and after surgery, and the other exposed to the ethanol carrier solution alone.

Each dog's behavior was videotaped for 30 minutes, and blood and saliva samples were obtained on the morning of the scheduled surgery. This was repeated in specially prepared intensive care unit cages that were either sprayed with pheromone following the manufacturer's recommendations or with the placebo spray. One surgeon performed the procedures, and the same anesthetic protocol was used in each case.

After surgery, the dogs were again transferred to prepared cages, and their behavior was reevaluated after they were able to stand. At this stage, blood and saliva were again sampled, and the dogs' pain was assessed by using a dynamic interaction test. The evaluations and sampling were repeated in the dogs' usual environment, and again at one, two, and eight days after surgery. All of the evaluations were videotaped and reviewed by a single investigator.

The treated dogs showed some beneficial effects—they displayed more alertness and visual exploration behaviors after surgery and had a significantly smaller decrease in postoperative prolactin concentration than did dogs in the untreated group. Prolactin has been shown in previous research to affect the neuroendocrine stress response and was notably influenced by pheromone exposure in this study.

The findings of this study suggest that it is possible to improve the overall experience and well-being of perioperative patients with the use of this synthetic pheromone. The study investigators suggest additional research to determine the pheromone's mechanism of action and explore various clinical applications.

Source: Siracusa C, Manteca X, Cuenca R, et al. Effects of a synthetic appeasing pheromone on behavioral, neuroendocrine, immune and acute-phase perioperative stress responses in dogs. J Am Vet Med Assoc 2010;237(6):673-681.