Compensatory Effects of ICV Grafted Adrenal Medullary Tissue for the Brain CA System Lesion in Ground Squirrels

It was postulated that a cessation of brain adrenergic activity might pre-cede the onset of entry into hibernation.Measurements of brain NE content in cer-tain hibernators have indicated that the level of NE during the hibernating bout was lower than the euthermic state during winter. Our precursor work verified that de-pletion of NE activity by intraventricular injection of 6-OH DA might have a facili-tating effect on the entrance of hibernation,largely shorten the induction period and lengthen the total hibernation time.In this work the medullary tissue of animal′s own adrenal gland were grafted into the lateral ventricle of 6-OH DA treated ground squirrels.The results proved that on the background of lowered catecholamine level grafted medullary tissue had compensatory effects for the CA lesion in hibernating behaviors. The total hibernat-ing time,number of hibernation bouts and length of the maximal hibernating bout were significantly decreased than that of the control,at all,showing opposite effects to those of 6-OH DA treatment.As a result,it gives a strong support to the postu-lation that involvement of brain CA system in the processing of hibernation bout.