Development of the response to adenosine during organ culture of young embryonic chick hearts

Young (3 days-old) embryonic chick hearts (i.e., prior to innervation) show little electrophysiological response to adenosine. However, during embryonic development the sensitivity to adenosine greatly increases. In the present experiments, in which the chick hearts were placed into organ culture, the sensitivity to adenosine was found to increase with time in culture. Thus, the ability of adenosine to slow the spontaneous heart rate became greater during the course of organ culture. These results suggest that physiological responses to adenosine continue to develop in organ culture, and that the increased sensitivity to adenosine seen in ovo may be independent from the development of sympathetic or parasympathetic innervation.