First Half Of Observation Period Research Articles

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

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 (10mg/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 10min. 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 120min. 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.

砂礫混合海岸における底質・地形変化モデルの構築

In this study, to clarify the forces affecting on the temporal-spatial variation of the median grain size and topographic change of the sand gravel beach, field observations were carried out for 3 years and a numerical model was developed. Study site is the east coast beach in the Narugashima Island located between inner bay - Osaka bay - and open sea - Kii channel -, in Seto Inland Sea, western Japan. From the result of field observations, the periodic disturbance in this beach was confirmed. It tends to be coarse at the first half of observation period and be fine at the second half of observation period. On the other hand, the result of numerical simulation shows that the blown sand is important factor affecting on the temporal-spatial distributions of the median grain size and topographic change in this beach.