Somatostatin in the retina

Area of Science:

• Neuroscience
• Molecular Biology
• Comparative Anatomy

Background:

• The neuropeptide somatostatin is encoded by a single gene in mammals, with high homology across species.
• Somatostatin and its precursor, prosomatostatin, are suitable for studying post-translational processing due to their conserved nature.

Purpose of the Study:

• To comparatively investigate the biosynthetic processing of somatostatin precursor in the retina across five species: frog, rat, gerbil, mink, and monkey.
• To quantify, characterize, and localize somatostatin and prosomatostatin using specific antibodies and in-situ hybridization.

Main Methods:

• Utilized antibodies against four putative parts of the prosomatostatin molecule.
• Employed biochemical and histochemical techniques for quantification, characterization, and localization.
• Applied in-situ hybridization with an antisense probe for somatostatin to identify producing cells.

Main Results:

• Somatostatin and prosomatostatin were detected in retinal extracts from all five species.
• Significant species-specific variations in retinal post-translational processing of prosomatostatin were observed.
• Identified different bioactive forms of somatostatin (SS-14 and SS-28) and fragments (proSS-64, somatostatin 1-28(1-12)) across species.

Conclusions:

• Somatostatin and prosomatostatin are highly conserved peptides in vertebrate retinae.
• Distinct species differences exist in the post-translational processing of somatostatin precursors.
• The physiological significance of these observed processing variations requires further investigation.