Stress as cause of signs and symptoms of pseudo-Cushing's syndrome in buffy-tufted marmosets (Callithrix aurita).

Hyperadrenocorticism is a medical condition caused by the increase in cortisol production by the cortex of the adrenal gland. Although infrequently described in most animal species, its naturally occurring form, called Cushing's syndrome, is the most prevalent endocrinopathy in dogs. Cushing's syndrome is also present in humans and might be confused with the pseudo-Cushing's syndrome (PCS), rarely described in animals. PCS shares many of the clinical and biochemical features of Cushing's syndrome. However, the hypercortisolemia seen is usually idiopathic and, in some circumstances, associated with psychological disruptions. This report describes PCS-like disorder in two marmosets Callithrix aurita that were exposed to environmental changes, suggesting stress as the main cause of the process and reviewing the mechanisms involved in the pathogeny of the two syndromes.

Diazepam-induced decrease in anxiety-like behaviors of marmoset monkeys exposed to a novel open-field.

Unfamiliar environments can be a source of stress, fear and anxiety for marmoset monkeys. In spite of existing data, the influence of putative anxiolytics on the effects of novel environments has yet to be tested in primates. Therefore, the behavior of adult black tufted-ear marmosets to a single brief (15 min) exposure to a novel environment was analyzed in the presence and absence of diazepam (DZP). Marmosets were pre-treated with vehicle (n=5) or diazepam (0.5 mg/kg, ip; n=5) and submitted to a 15 min free exploration trial within a rectangular open-field arena. DZP-treated subjects, compared to vehicle controls, demonstrated significantly lower rates of (phee) contact calls and exploration, while a higher scan duration. Sojourn time in the arena's central zone was also significantly higher in the former group and sedation was not observed. Thus, pre-treatment with the benzodiazepine DZP decreased several anxiety-related behaviors induced by subjecting the marmosets to a new environment. The results also indicate that, as with rodent subjects, the open-field may provide a useful simple paradigm for assessing anxiety-like behaviors in this primate and, as such, constitutes a unique opportunity for direct comparative studies between rodents and marmoset monkeys in terms of anxiety and/or sedation.