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Glycine increases the number of somatostatin receptors and somatostatin-mediated inhibition of the adenylate cyclase system in the rat hippocampus.
J Neurosci Res. 1996 Feb 01; 43(3):346-54.JN

Abstract

The glycine and somatostatin (SS) neurotransmission systems in the brain have been implicated in the function of sensory, motor, and nociceptive pathways. To investigate a possible relationship between these two components, we studied the influence of glycine on the binding of 125I-Tyr11-SS to its receptors and on SS-like immunoreactivity (SSLI) levels in the rat hippocampus and frontoparietal cortex. An intracerebroventricular (i.c.v.) dose of 16 or 160 nmol of glycine induced an increase in the total number of specific SS receptors in the hippocampus but not in the frontoparietal cortex at 15 min following injection, with no changes in the affinity constant. This effect seems to be mediated by inhibitory strychnine-sensitive glycine receptors since pretreatment with the antagonist strychnine (80 micrograms/100 g body weight, intravenously) abolished this response. No significant changes in SSLI content were detected in either brain region of glycine- and strychnine plus glycine-treated rats as compared to control values. Since SS receptors are coupled via guanine nucleotide-binding G proteins to the adenylyl cyclase (AC) system, we also examined the inhibitory effects of SS and the guanine nucleotide Gpp(NH)p on AC activity in hippocampal membranes of control, glycine- and strychnine plus glycine-treated rats since the increase in SS receptors was observed only in this brain area. No significant differences were observed for the forskolin (FK)-stimulated AC enzyme activities in hippocampal membranes from all the experimental groups studied. In the hippocampus of the glycine- (160 nmol) treated group, however, basal AC activity was significantly lower, and the capacity of SS to inhibit FK-stimulated AC activity was increased as compared to the control group. Pretreatment with strychnine prevented the increase in SS-mediated inhibition of AC activity. The functional activity of the inhibitory guanine nucleotide-binding protein Gi, as determined by the inhibitory effect of the stable GTP analogue Gpp(NH)p on FK-stimulated AC activity, was significantly higher in hippocampal membranes of glycine- (160 nmol) treated rats as compared to controls. This suggests that the increased inhibition of AC activity by SS in the glycine-treated group may be due to the increase in Gi activity and/or the increase in the number of SS receptors observed. Alternatively, the greater Gi activity may be responsible for the increased binding of 125I-Tyr11-SS to its receptors observed after glycine administration. Altogether, these data suggest that the hippocampal somatostatinergic system can be regulated by strychnine-sensitive glycine receptors in the rat.

Authors+Show Affiliations

Departamento de Bioquímica y Biología Molecular, Universidad de Alcalá, Madrid, Spain.No affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

8714523

Citation

Puebla, L, and E Arilla. "Glycine Increases the Number of Somatostatin Receptors and Somatostatin-mediated Inhibition of the Adenylate Cyclase System in the Rat Hippocampus." Journal of Neuroscience Research, vol. 43, no. 3, 1996, pp. 346-54.
Puebla L, Arilla E. Glycine increases the number of somatostatin receptors and somatostatin-mediated inhibition of the adenylate cyclase system in the rat hippocampus. J Neurosci Res. 1996;43(3):346-54.
Puebla, L., & Arilla, E. (1996). Glycine increases the number of somatostatin receptors and somatostatin-mediated inhibition of the adenylate cyclase system in the rat hippocampus. Journal of Neuroscience Research, 43(3), 346-54.
Puebla L, Arilla E. Glycine Increases the Number of Somatostatin Receptors and Somatostatin-mediated Inhibition of the Adenylate Cyclase System in the Rat Hippocampus. J Neurosci Res. 1996 Feb 1;43(3):346-54. PubMed PMID: 8714523.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Glycine increases the number of somatostatin receptors and somatostatin-mediated inhibition of the adenylate cyclase system in the rat hippocampus. AU - Puebla,L, AU - Arilla,E, PY - 1996/2/1/pubmed PY - 2000/6/20/medline PY - 1996/2/1/entrez SP - 346 EP - 54 JF - Journal of neuroscience research JO - J Neurosci Res VL - 43 IS - 3 N2 - The glycine and somatostatin (SS) neurotransmission systems in the brain have been implicated in the function of sensory, motor, and nociceptive pathways. To investigate a possible relationship between these two components, we studied the influence of glycine on the binding of 125I-Tyr11-SS to its receptors and on SS-like immunoreactivity (SSLI) levels in the rat hippocampus and frontoparietal cortex. An intracerebroventricular (i.c.v.) dose of 16 or 160 nmol of glycine induced an increase in the total number of specific SS receptors in the hippocampus but not in the frontoparietal cortex at 15 min following injection, with no changes in the affinity constant. This effect seems to be mediated by inhibitory strychnine-sensitive glycine receptors since pretreatment with the antagonist strychnine (80 micrograms/100 g body weight, intravenously) abolished this response. No significant changes in SSLI content were detected in either brain region of glycine- and strychnine plus glycine-treated rats as compared to control values. Since SS receptors are coupled via guanine nucleotide-binding G proteins to the adenylyl cyclase (AC) system, we also examined the inhibitory effects of SS and the guanine nucleotide Gpp(NH)p on AC activity in hippocampal membranes of control, glycine- and strychnine plus glycine-treated rats since the increase in SS receptors was observed only in this brain area. No significant differences were observed for the forskolin (FK)-stimulated AC enzyme activities in hippocampal membranes from all the experimental groups studied. In the hippocampus of the glycine- (160 nmol) treated group, however, basal AC activity was significantly lower, and the capacity of SS to inhibit FK-stimulated AC activity was increased as compared to the control group. Pretreatment with strychnine prevented the increase in SS-mediated inhibition of AC activity. The functional activity of the inhibitory guanine nucleotide-binding protein Gi, as determined by the inhibitory effect of the stable GTP analogue Gpp(NH)p on FK-stimulated AC activity, was significantly higher in hippocampal membranes of glycine- (160 nmol) treated rats as compared to controls. This suggests that the increased inhibition of AC activity by SS in the glycine-treated group may be due to the increase in Gi activity and/or the increase in the number of SS receptors observed. Alternatively, the greater Gi activity may be responsible for the increased binding of 125I-Tyr11-SS to its receptors observed after glycine administration. Altogether, these data suggest that the hippocampal somatostatinergic system can be regulated by strychnine-sensitive glycine receptors in the rat. SN - 0360-4012 UR - https://www.unboundmedicine.com/medline/citation/8714523/Glycine_increases_the_number_of_somatostatin_receptors_and_somatostatin_mediated_inhibition_of_the_adenylate_cyclase_system_in_the_rat_hippocampus_ L2 - https://doi.org/10.1002/(SICI)1097-4547(19960201)43:3<346::AID-JNR9>3.0.CO;2-J DB - PRIME DP - Unbound Medicine ER -