Somatostatin and somatostatin subtype 2A expression in the mammalian retina

Johnson, John L.; Rickman, Doug; Brecha, Nicholas C.

doi:10.1002/1097-0029(20000715)50:2<103::aid-jemt2>3.0.co;2-x

Cited by 30 publications

(14 citation statements)

References 58 publications

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“…Somatostatin causes general excitation, occurring with a threshold concentration of about 100 n m ; it also increases the signal‐to‐noise ratio (ratio of light‐evoked to spontaneous spiking, which results from a decrease in spontaneous activity and a concomitant increase in light‐evoked spiking) and leads to a shift in centre–surround balance towards a more dominant centre . In the outer retina, mostly SST2 receptors are found . Phototransduction and light adaptation processes are influenced by Sst directly or through dopaminergic and NOergic pathways , mainly activating SST2A receptors.…”

Section: Neuropeptides In the Human Retinamentioning

confidence: 99%

“…Five seven‐transmembrane somatostatin receptor types have been cloned, of which SST1, 2 and 4 all upregulate phospholipase C and phospholipase A 2 , while downregulating adenylyl cyclase . In the retina, SST1, 2 and 4 receptors are present in the highest quantities; the SST1 receptor is an autoreceptor controlling somatostatin release, while the SST2 and 4 receptors are able to regulate voltage‐gated ion channels of retinal neurons .…”

Section: Neuropeptides and Diabetic Retinopathymentioning

confidence: 99%

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Neuropeptides and diabetic retinopathy

Gábriel¹

2013

Brit J Clinical Pharma

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Diabetic retinopathy, a common complication of diabetes, develops in 75% of patients with type 1 and 50% of patients with type 2 diabetes, progressing to legal blindness in about 5%. In the recent years, considerable efforts have been put into finding treatments for this condition. It has been discovered that peptidergic mechanisms (neuropeptides and their analogues, activating a diverse array of signal transduction pathways through their multiple receptors) are potentially important for consideration in drug development strategies. A considerable amount of knowledge has been accumulated over the last three decades on human retinal neuropeptides and those elements in the pathomechanisms of diabetic retinopathy which might be related to peptidergic signal transduction. Here, human retinal neuropeptides and their receptors are reviewed, along with the theories relevant to the pathogenesis of diabetic retinopathy both in humans and in experimental models. By collating this information, the curative potential of certain neupeptides and their analogues/antagonists can also be discussed, along with the existing clinical treatments of diabetic retinopathy. The most promising peptidergic pathways for which treatment strategies may be developed at present are stimulation of the somatostatin-related pathway and the pituitary adenylyl cyclase-activating polypeptide-related pathway or inhibition of angiotensinergic mechanisms. These approaches may result in the inhibition of vascular endothelial growth factor production and neuronal apoptosis; therefore, both the optical quality of the image and the processing capability of the neural circuit in the retina may be saved.

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Section: Neuropeptides In the Human Retinamentioning

confidence: 99%

Section: Neuropeptides and Diabetic Retinopathymentioning

confidence: 99%

Neuropeptides and diabetic retinopathy

Gábriel¹

2013

Brit J Clinical Pharma

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“…Other neuroactive substances, such as dopamine, somatostatin, and substance P (Witkovsky and Schutte, 1991;Casini et al, 1997;Johnson et al, 1998Johnson et al, , 1999, are also distributed away from their receptors in the retina. For example, in the rat retina, somatostatin is localized to amacrine and displaced amacrine cells and processes that ramify primarily in strata 1 and 5 of the IPL, whereas the somatostatin receptor 2A is localized to cone photoreceptors, horizontal cells, bipolar cells, and amacrine cells (Johnson et al, 1998(Johnson et al, , 1999(Johnson et al, , 2000 and the somatostatin receptor 4 is localized to multistratified ganglion cells (Vila and Brecha, 2001). Dopamine is expressed primarily by wide-field amacrine cells with processes that ramify in strata 1 of the IPL (Nguyen-Legros et al, 1997), whereas dopamine receptors are found throughout the retina, including horizontal cells (Firth et al, 1997;Nguyen-Legros et al, 1999).…”

Section: Npy As a Paracrine Neuromodulator In The Retinamentioning

confidence: 99%

Localization of neuropeptide Y1 receptor immunoreactivity in the rat retina and the synaptic connectivity of Y1 immunoreactive cells

D'Angelo¹,

Oh²,

Chun³

et al. 2002

J of Comparative Neurology

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Neuropeptide Y (NPY), an inhibitory neuropeptide expressed by a moderately dense population of wide-field amacrine cells in the rat retina, acts through multiple (Y1-y6) G-protein-coupled receptors. This study determined the cellular localization of Y1 receptors and the synaptic connectivity of Y1 processes in the inner plexiform layer (IPL) of the rat retina. Specific Y1 immunoreactivity was localized to horizontal cell bodies in the distal inner nuclear layer and their processes in the outer plexiform layer. Immunoreactivity was also prominent in cell processes located in strata 2 and 4, and puncta in strata 4 and 5 of the IPL. Double-label immunohistochemical experiments with calbindin, a horizontal cell marker, confirmed Y1 immunostaining in all horizontal cells. Double-label immunohistochemical experiments, using antibodies to choline acetyltransferase and vesicular acetylcholine transporter to label cholinergic amacrine cell processes, demonstrated that Y1 immunoreactivity in strata 2 and 4 of the IPL was localized to cholinergic amacrine cell processes. Electron microscopic studies of the inner retina showed that Y1-immunostained amacrine cell processes and puncta received synaptic inputs from unlabeled amacrine cell processes (65.2%) and bipolar cell axon terminals (34.8%). Y1-immunoreactive amacrine cell processes most frequently formed synaptic outputs onto unlabeled amacrine cell processes (34.0%) and ganglion cell dendrites (54.1%). NPY immunoreactivity in the rat retina is distributed primarily to strata 1 and 5 of the IPL, and the present findings, thus, suggest that NPY acts in a paracrine manner on Y1 receptors to influence both horizontal and amacrine cells. Indexing termsamacrine cells; choline acetyltransferase; calcium binding protein; horizontal cells; neuropeptides Neuropeptide Y (NPY) has multiple physiologic actions in both the central and peripheral nervous system, including effects on blood flow, memory retention, food intake, epilepsy, and pain (Lundberg et al., 1996;Munglani et al., 1996;Balasubramaniam, 1997;Blomqvist and Herzog, 1997;Thorsell et al., 2000;Furtinger et al., 2001;Naveilhan et al., 2001). These NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript effects are mediated by means of at least five G-protein-coupled receptors, designated as Y1, Y2, Y4, Y5, and y6, which are coupled to pertussis toxin-sensitive inhibitory Gproteins (Lundberg et al., 1996;Munglani et al., 1996;Balasubramaniam, 1997;Blomqvist and Herzog, 1997;Michel et al., 1998). Y-receptors have been localized to specific regions of the central and peripheral nervous system by receptor binding autoradiography, immunohistochemistry, and in situ hybridization (Zhang et al., 1994;Bao et al., 1997;Jacques et al., 1997;Dumont et al., 1998;Hökfelt et al., 1998;Gackenheimer et al., 2001). Y1 receptor is the most studied Y-receptor and it plays key roles in many of the central and peripheral effects of NPY (Lundberg et al., 1996;Munglani et al., 1996;Balasubramaniam, 1997;Blomqvist and H...

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“…In the retina, SRIF is predominantly, if not exclusively, expressed by a limited number of widely ramifying and sparsely distributed amacrine cells (for references, see Johnson et al 2000). In contrast, the SRIF receptors (sst 1 -sst 5 ) are widely distributed to several retinal cell populations (for references, see Cervia et al 2008a).…”

Section: Introductionmentioning

confidence: 98%

Protective role of somatostatin receptor 2 against retinal degeneration in response to hypoxia

Monte

Latina

Cupisti

et al. 2012

Naunyn-Schmiedeberg's Arch Pharmacol

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In mouse retinal explants, octreotide, a somatostatin [somatotropin release-inhibiting factor (SRIF)] receptor 2 (sst(2)) agonist, prevents the hypoxia-induced vascular endothelial growth factor upregulation. In mice with oxygen-induced retinopathy (OIR), a model of retinopathy of prematurity, either sst(2) overexpression or octreotide have been found to limit hypoxia-induced angiogenic processes. Here, we investigated whether sst(2) influences retinal degeneration in response to hypoxia in wild-type (WT), sst(1)- and sst(2)-knockout (KO) mice. In retinal explants, we determined the role of sst(2) on apoptotic signals. In control condition, caspase-3 activity and the Bax/Bcl-2 ratio were lower in sst(1)-KO than in WT, but higher in sst(2)-KO than in WT retinas. In all strains, a comparable increase in caspase-3 activity and the Bax/Bcl-2 ratio was observed after hypoxia. The hypoxia-induced increase in apoptotic signals was recovered by octreotide in both WT and sst(1)-KO retinas. To investigate the role of sst(2) on retinal function, we recorded electroretinogram (ERG) in response to light flashes in OIR mice. ERG responses did not differ between WT and KO mice with the exception of oscillatory potentials (OPs) which, in sst(1)-KO mice, displayed much larger amplitude. In all strains, hypoxia drastically reduced a-, b-waves and OPs. In both WT and sst(1)-KO mice, octreotide recovered a- and b-waves, but did not recover OPs in sst(1)-KO mice. Neither apoptotic signals nor ERG was affected by octreotide in sst(2)-KO mice. These results show that sst(2) may protect retinal cells from hypoxia, thus implementing the background to establish potential pharmacological targets based on sst(2) pharmacology.

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Somatostatin and somatostatin subtype 2A expression in the mammalian retina

Cited by 30 publications

References 58 publications

Neuropeptides and diabetic retinopathy

Neuropeptides and diabetic retinopathy

Localization of neuropeptide Y1 receptor immunoreactivity in the rat retina and the synaptic connectivity of Y1 immunoreactive cells

Protective role of somatostatin receptor 2 against retinal degeneration in response to hypoxia

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