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Delayed stress-induced antinociceptive effect of nitric oxide synthase inhibition in the dentate gyrus of rats.
Pharmacol Biochem Behav. 2002 Dec; 74(1):149-56.PB

Abstract

Stimulation of the hippocampal formation can modulate nociceptive mechanisms, whereas painful stimuli can activate this structure. Stress exposure can produce plastic changes in the hippocampus. Nitric oxide (NO) is an important neuroregulatory agent present in the hippocampus. The objective of the present study was to investigate the effects of intrahippocampal administration of N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME), an inhibitor of NO synthase (NOS), on nociceptive processes in stressed and nonstressed rats. Male Wistar rats (n=6-11/group) received unilateral microinjection of L-NAME (50-300 nmol/0.2 microl) into the dentate gyrus (DG) of the dorsal hippocampus. Immediately after the injection tail-flick reflex latency was measured. Stressed animals were submitted to 2 h of restraint and tested immediately or 1, 2, 5 or 10 days later. L-NAME failed to modify nociception in nonstressed rats. However, 5 days after, restraint L-NAME, at all doses tested, produced an antinociceptive effect (ANOVA, P<.05). The dose-response curve had an inverted U shape. L-NAME antinociceptive effect was antagonized by previous treatment with L-arginine (150 nmol/0.2 microl, P<.05). The results suggest that the modulation of nociceptive processes by NO in the dorsal hippocampus is dependent on previous stress exposure and on poststress interval.

Authors+Show Affiliations

Department of Physiology, Medical School, Campus USP, SP, Ribeirão Preto, Brazil.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

12376162

Citation

Echeverry, Marcela B., et al. "Delayed Stress-induced Antinociceptive Effect of Nitric Oxide Synthase Inhibition in the Dentate Gyrus of Rats." Pharmacology, Biochemistry, and Behavior, vol. 74, no. 1, 2002, pp. 149-56.
Echeverry MB, Guimarães FS, Oliveira MA, et al. Delayed stress-induced antinociceptive effect of nitric oxide synthase inhibition in the dentate gyrus of rats. Pharmacol Biochem Behav. 2002;74(1):149-56.
Echeverry, M. B., Guimarães, F. S., Oliveira, M. A., do Prado, W. A., & Del Bel, E. A. (2002). Delayed stress-induced antinociceptive effect of nitric oxide synthase inhibition in the dentate gyrus of rats. Pharmacology, Biochemistry, and Behavior, 74(1), 149-56.
Echeverry MB, et al. Delayed Stress-induced Antinociceptive Effect of Nitric Oxide Synthase Inhibition in the Dentate Gyrus of Rats. Pharmacol Biochem Behav. 2002;74(1):149-56. PubMed PMID: 12376162.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Delayed stress-induced antinociceptive effect of nitric oxide synthase inhibition in the dentate gyrus of rats. AU - Echeverry,Marcela B, AU - Guimarães,Francisco S, AU - Oliveira,Marina A, AU - do Prado,William A, AU - Del Bel,Elaine A, PY - 2002/10/12/pubmed PY - 2003/3/22/medline PY - 2002/10/12/entrez SP - 149 EP - 56 JF - Pharmacology, biochemistry, and behavior JO - Pharmacol Biochem Behav VL - 74 IS - 1 N2 - Stimulation of the hippocampal formation can modulate nociceptive mechanisms, whereas painful stimuli can activate this structure. Stress exposure can produce plastic changes in the hippocampus. Nitric oxide (NO) is an important neuroregulatory agent present in the hippocampus. The objective of the present study was to investigate the effects of intrahippocampal administration of N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME), an inhibitor of NO synthase (NOS), on nociceptive processes in stressed and nonstressed rats. Male Wistar rats (n=6-11/group) received unilateral microinjection of L-NAME (50-300 nmol/0.2 microl) into the dentate gyrus (DG) of the dorsal hippocampus. Immediately after the injection tail-flick reflex latency was measured. Stressed animals were submitted to 2 h of restraint and tested immediately or 1, 2, 5 or 10 days later. L-NAME failed to modify nociception in nonstressed rats. However, 5 days after, restraint L-NAME, at all doses tested, produced an antinociceptive effect (ANOVA, P<.05). The dose-response curve had an inverted U shape. L-NAME antinociceptive effect was antagonized by previous treatment with L-arginine (150 nmol/0.2 microl, P<.05). The results suggest that the modulation of nociceptive processes by NO in the dorsal hippocampus is dependent on previous stress exposure and on poststress interval. SN - 0091-3057 UR - https://www.unboundmedicine.com/medline/citation/12376162/Delayed_stress_induced_antinociceptive_effect_of_nitric_oxide_synthase_inhibition_in_the_dentate_gyrus_of_rats_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0091305702009644 DB - PRIME DP - Unbound Medicine ER -