NADPH-diaphorase colocalization with somatostatin receptor subtypes sst2A and sst2B in the retina.
OBJECTIVE
To investigate the differential localization of somatotropin release-inhibitory factor (SRIF) receptor subtypes (sst2A and sst2B) and their possible colocalization with reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase in the rat and rabbit retina.


METHODS
Polyclonal antibodies raised against sst2A and sst2B receptors were applied to 10- to 14-microm cryostat sections of rat and rabbit retinas fixed in paraformaldehyde. NADPH-diaphorase reactivity was assessed histochemically. Double labeling was performed for sst2A or sst2B receptors with NADPH-diaphorase, and with markers for the cell types present in the retina (protein kinase C [PKC], tyrosine hydroxylase; [TH], calbindin, and recoverin).


RESULTS
sst2A immunoreactivity was detected in rod bipolar cells and colocalized with NADPH-diaphorase in the rabbit, but not the rat, retina. sst2B was present only in photoreceptor cells of the rat and colocalized with NADPH-diaphorase.


CONCLUSIONS
These results suggest that SRIF, acting through sst2A receptors in bipolar cells and sst2B receptors in photoreceptor cells, may affect nitric oxide function in the rabbit and rat retina.
Vasilaki
A
A
Laboratory of Pharmacology, Department of Basic Sciences, Faculty of Medicine, University of Crete, Heraclion, Greece.
Gardette
R
R
Epelbaum
J
J
Thermos
K
K
D000818:Animals; D000911:Antibodies, Monoclonal; D064026:Calbindins; D002135:Calcium-Binding Proteins / Q000032:analysis; D005136:Eye Proteins / Q000032:analysis*; D019084:Fluorescent Antibody Technique, Indirect; D051597:Hippocalcin; D008074:Lipoproteins; D008297:Male; D008856:Microscopy, Fluorescence; D009252:NADPH Dehydrogenase / Q000032:analysis*; D009419:Nerve Tissue Proteins; D011493:Protein Kinase C / Q000032:analysis; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D017481:Receptors, Somatostatin / Q000032:analysis*; D051603:Recoverin; D012160:Retina / Q000737:chemistry*; D064030:S100 Calcium Binding Protein G / Q000032:analysis; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis
D000911:Antibodies, Monoclonal; D064026:Calbindins; D002135:Calcium-Binding Proteins; D005136:Eye Proteins; D008074:Lipoproteins; D009419:Nerve Tissue Proteins; C496733:Rcvrn protein, rat; D017481:Receptors, Somatostatin; D064030:S100 Calcium Binding Protein G; C115977:Sstr2 protein, rat; C106140:somatostatin receptor sst2A; D051603:Recoverin; D051597:Hippocalcin; D014446:Tyrosine 3-Monooxygenase; D009252:NADPH Dehydrogenase; D011493:Protein Kinase C