COMPARISON OF [I-125] IODOMELATONIN BINDING-SITES IN INFANT CEREBELLUM OF SUDDEN-INFANT-DEATH-SYNDROME AND NONSUDDEN INFANT DEATH SYNDROME

[I-125]Iodomelatonin binding sites in human infant cerebellum were stu died by radioligand receptor binding assay and in vitro quantitative a utoradiography. The binding sites characterized in membrane preparatio ns revealed saturable, reversible and highly specific binding sites wi th a K-d value of 21.2 +/- 8.33 pM and a B-max value of 2.02 +/- 0.52 fmol/mg protein. 10 mu M of GTP gamma S significantly reduced the bind ing capacity, suggesting the possible G-protein coupling of the bindin g sites. Autoradiographic study showed that the labelling was mainly l ocated in the cerebellar cortex. On comparison of the binding paramete rs from cerebellum of sudden infant death syndrome (SIDS) and non-SIDS infants, no significant change in binding capacity and binding affini ty was detected. These findings suggest that the binding sites in cere bellum may not be related to the etiology of SIDS.