Effect of synthetic cathinones: Mephedrone, butylone and 3,4 methylene-dioxypyrovalerone (MDPV) on social separation induced distress vocalization, vigilance and postural control of young domestic chicks

• Mephedrone and MDPV enhanced distress calls of socially isolated domestic chicks.
• Butylone caused postural disorder and hyperventilation in chicks.
• MDPV increased wakeful activity and pecking in chicks.
• Closely related cathinones exert different behavioral effects.

Designer drugs have become a distinct social problem and health hazard in Europe and US, and their abuse has increased dramatically in the last decade. Selective effects of these agents on animal behavioral parameters may help in better understanding of the potential risks of human drug abuse. In the present study, the effects of three different abusive agents of the cathinone family, mephedrone, butylone and 3,4 methylene-dioxypyrovalerone (MDPV) were tested in young domestic chicks, following administration of single intraperitoneal injections (10 mg/bwt). Early maturing (precocial) birds are particularly suited for investigation of isolation stress-related behavioral response and stereotypic or targeted pecking. Both mephedrone and MDPV increased the frequency of distress calls of socially isolated birds as measured over a period of 10 min. While this effect of mephedrone was only evident in the first half of observation period, an increase with MDPV was more lasting. Though increased non-distress vocalization, butylone failed to enhance distress calls probably due to a general adverse effect on muscle tone. Apart from its effect on distress vocalization, mephedrone did not alter the behavior of chicks. However, both butylone and MDPV showed prominent behavioral changes, which were examined in another set of long term experiments, over a period of 120 min. Butylone caused hyperventilation and a robust impairment of postural control, whereas neither the wakeful activity level, nor the pecking frequency was significantly affected. Conversely, no hyperventilation or postural disorder was observed with MDPV, however, both waking state and pecking were significantly enhanced. The results may be relevant to potentially different and specific effects of cathinone drugs under stress-related conditions, as well as on other physiological and behavioral parameters, even in case of closely related compounds.