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Differential coupling of somatostatin1 receptors to adenylyl cyclase in the rat striatum vs. the pituitary and other regions of the rat brain.
J Pharmacol Exp Ther. 1992 Feb; 260(2):841-8.JP

Abstract

Subtypes of somatostatin (SRIF) receptors are expressed in the rat brain and may mediate the diverse actions of SRIF. In the present study we show that subtypes of SRIF receptors in different regions of the rat brain are differentially sensitive to the cyclic hexapeptide SRIF analog, MK 678. SRIF1 receptors are sensitive to MK 678 and found in high density in the cortex, hippocampus and striatum, as well as in the anterior pituitary. The pituitary appears to express only the SRIF1 receptor. The cortex, hippocampus and striatum also express SRIF2, or MK 678-insensitive, receptors. The proportion of SRIF1 receptors varies in different brain regions. In the cortex and hippocampus, SRIF1 receptors comprise approximately 50% of the total SRIF receptor population, whereas in the striatum SRIF1 receptors comprise the majority (86%) of SRIF receptors. SRIF1 receptors in the pituitary, cortex and hippocampus mediate, at least in part, the ability of SRIF to inhibit forskolin-stimulated adenylyl cyclase activity as MK 678 produced significant inhibition of activity in these tissues. However, in the striatum, MK 678 had no significant effect on forskolin-stimulated adenylyl cyclase activity, despite a significant inhibition produced by SRIF. The specific labeling of these receptors in the striatum by [125I]MK 678 is abolished in the presence of high concentrations of the nonhydrolyzable GTP analog, GTP gamma S, suggesting that SRIF1 receptors in this brain region are coupled to G proteins. The SRIF1 receptors in the striatum may be coupled via G proteins to cellular transducing systems other than adenylyl cyclase.

Authors+Show Affiliations

Raynor K
Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia.
Reisine T
No affiliation info available

MeSH

Adenylyl CyclasesAnimalsCerebral CortexCorpus StriatumGTP-Binding ProteinsGuanosine 5'-O-(3-Thiotriphosphate)HippocampusMaleOctreotidePeptides, CyclicPituitary Gland, AnteriorRatsRats, Inbred StrainsReceptors, NeurotransmitterReceptors, SomatostatinSomatostatin

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

1346648

Citation

Raynor, K, and T Reisine. "Differential Coupling of Somatostatin1 Receptors to Adenylyl Cyclase in the Rat Striatum Vs. the Pituitary and Other Regions of the Rat Brain." The Journal of Pharmacology and Experimental Therapeutics, vol. 260, no. 2, 1992, pp. 841-8.
Raynor K, Reisine T. Differential coupling of somatostatin1 receptors to adenylyl cyclase in the rat striatum vs. the pituitary and other regions of the rat brain. J Pharmacol Exp Ther. 1992;260(2):841-8.
Raynor, K., & Reisine, T. (1992). Differential coupling of somatostatin1 receptors to adenylyl cyclase in the rat striatum vs. the pituitary and other regions of the rat brain. The Journal of Pharmacology and Experimental Therapeutics, 260(2), 841-8.
Raynor K, Reisine T. Differential Coupling of Somatostatin1 Receptors to Adenylyl Cyclase in the Rat Striatum Vs. the Pituitary and Other Regions of the Rat Brain. J Pharmacol Exp Ther. 1992;260(2):841-8. PubMed PMID: 1346648.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Differential coupling of somatostatin1 receptors to adenylyl cyclase in the rat striatum vs. the pituitary and other regions of the rat brain. AU - Raynor,K, AU - Reisine,T, PY - 1992/2/1/pubmed PY - 1992/2/1/medline PY - 1992/2/1/entrez SP - 841 EP - 8 JF - The Journal of pharmacology and experimental therapeutics JO - J Pharmacol Exp Ther VL - 260 IS - 2 N2 - Subtypes of somatostatin (SRIF) receptors are expressed in the rat brain and may mediate the diverse actions of SRIF. In the present study we show that subtypes of SRIF receptors in different regions of the rat brain are differentially sensitive to the cyclic hexapeptide SRIF analog, MK 678. SRIF1 receptors are sensitive to MK 678 and found in high density in the cortex, hippocampus and striatum, as well as in the anterior pituitary. The pituitary appears to express only the SRIF1 receptor. The cortex, hippocampus and striatum also express SRIF2, or MK 678-insensitive, receptors. The proportion of SRIF1 receptors varies in different brain regions. In the cortex and hippocampus, SRIF1 receptors comprise approximately 50% of the total SRIF receptor population, whereas in the striatum SRIF1 receptors comprise the majority (86%) of SRIF receptors. SRIF1 receptors in the pituitary, cortex and hippocampus mediate, at least in part, the ability of SRIF to inhibit forskolin-stimulated adenylyl cyclase activity as MK 678 produced significant inhibition of activity in these tissues. However, in the striatum, MK 678 had no significant effect on forskolin-stimulated adenylyl cyclase activity, despite a significant inhibition produced by SRIF. The specific labeling of these receptors in the striatum by [125I]MK 678 is abolished in the presence of high concentrations of the nonhydrolyzable GTP analog, GTP gamma S, suggesting that SRIF1 receptors in this brain region are coupled to G proteins. The SRIF1 receptors in the striatum may be coupled via G proteins to cellular transducing systems other than adenylyl cyclase. SN - 0022-3565 UR - https://www.unboundmedicine.com/medline/citation/1346648/Differential_coupling_of_somatostatin1_receptors_to_adenylyl_cyclase_in_the_rat_striatum_vs__the_pituitary_and_other_regions_of_the_rat_brain_ DB - PRIME DP - Unbound Medicine ER -