Pre-pro-somatostatin (PSS-III) may have cortistatin (CTS)-like functions in fish

CANOSA LF; PETER RE

Uppsala, Sweden

Congreso; 22nd Conference of European Comparative Endocrinologists; 2004

This study analyzes the changes in gene expression of PSS-I (encodes for somatostatin (SS)-14) and PSS-III (encodes for [Pro2]-SS-14; structurally related to CTS) in relation to the daily light cycle in goldfish brain. CTS has specific sleep-promoting effects in rodents and its expression levels change during the day, being maximum at the end of the active phase. In this study, goldfish were acclimatized to a 16:8 D-L cycle (light phase from 10:00 to 18:00) for two months and sampled every two hours from 6:00 to 22:00. The brain was dissected and the telencephalon-preoptic area (Tel-POA) and optic tectum-thalamus (OT-T) retained for analysis. The PSS-I and PSS-III expression level was determined by slot-blot. The results indicate that the expression of PSS-I correlates with the light cycle only in OT-T. PSS-III gene expression correlates with the light cycle in both brain areas studied. In Tel-POA, PSS-III reaches the minimum level at the beginning of and the maximum level late in the active phase, similar to CTS in rodents. These results suggest that PSS-III from the Tel-POA as well as PSS-I and PSS-III from the OT-T could be involved in the control of the activity cycles in goldfish. Alternatively, PSS-I and PSS-III from the OT-T might be involved in processing of visual inputs.