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5-HT(1A) and 5-HT(2A) receptors in the rat dorsal periaqueductal gray mediate the antipanic-like effect induced by the stimulation of serotonergic neurons in the dorsal raphe nucleus.
Psychopharmacology (Berl). 2005 Dec; 183(3):314-21.P

Abstract

RATIONALE

It has been proposed that the serotonergic pathway that connects the dorsal raphe nucleus (DRN) to the dorsal periaqueductal gray (DPAG) is implicated in the regulation of escape, a behavior that has been related to panic.

OBJECTIVES

We further evaluated this hypothesis by investigating whether intra-DRN injection of the 5-HT(1A) receptor antagonist WAY-100635 changes the escape response of rats submitted to the elevated T-maze. This test also measures inhibitory avoidance, which has been associated with generalized anxiety disorder. We also investigated whether the 5-HT(1A) and 5-HT(2A) receptors in the DPAG mediate the behavioral consequences induced by the injection of WAY-100635 into the DRN.

RESULTS

Intra-DRN injection of WAY-100635 facilitated inhibitory avoidance, while impairing escape. The same effect was obtained after intra-DRN injection of the glutamate receptor agonist kainic acid. Preadministration of WAY-100635 into the DPAG counteracted the effect induced by intra-DRN injection of WAY-100635 and of kainic acid on escape, but not on inhibitory avoidance. Preadministration of the preferential 5-HT(2A) receptor antagonist ketanserin into the DPAG abolished the effects of intra-DRN injection of WAY-100635 on both elevated T-maze tasks.

CONCLUSION

The results are indicative that 5-HT(1A) autoreceptors in the DRN are under tonic inhibitory influence by endogenous 5-HT. The effects of 5-HT release in the DPAG after intra-DRN injection of WAY-100635 and kainic acid on inhibitory avoidance and escape involve different 5-HT receptor subtypes. Whereas 5-HT(2A) receptors in the DPAG seem to mediate the effect of 5-HT on both behaviors, 5-HT(1A) receptors are only involved in the regulation of escape.

Authors+Show Affiliations

Department of Pharmacology, School of Medicine, University of São Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, Brazil.No affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

16231166

Citation

Pobbe, Roger L H., and Hélio Zangrossi. "5-HT(1A) and 5-HT(2A) Receptors in the Rat Dorsal Periaqueductal Gray Mediate the Antipanic-like Effect Induced By the Stimulation of Serotonergic Neurons in the Dorsal Raphe Nucleus." Psychopharmacology, vol. 183, no. 3, 2005, pp. 314-21.
Pobbe RL, Zangrossi H. 5-HT(1A) and 5-HT(2A) receptors in the rat dorsal periaqueductal gray mediate the antipanic-like effect induced by the stimulation of serotonergic neurons in the dorsal raphe nucleus. Psychopharmacology (Berl). 2005;183(3):314-21.
Pobbe, R. L., & Zangrossi, H. (2005). 5-HT(1A) and 5-HT(2A) receptors in the rat dorsal periaqueductal gray mediate the antipanic-like effect induced by the stimulation of serotonergic neurons in the dorsal raphe nucleus. Psychopharmacology, 183(3), 314-21.
Pobbe RL, Zangrossi H. 5-HT(1A) and 5-HT(2A) Receptors in the Rat Dorsal Periaqueductal Gray Mediate the Antipanic-like Effect Induced By the Stimulation of Serotonergic Neurons in the Dorsal Raphe Nucleus. Psychopharmacology (Berl). 2005;183(3):314-21. PubMed PMID: 16231166.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - 5-HT(1A) and 5-HT(2A) receptors in the rat dorsal periaqueductal gray mediate the antipanic-like effect induced by the stimulation of serotonergic neurons in the dorsal raphe nucleus. AU - Pobbe,Roger L H, AU - Zangrossi,Hélio,Jr Y1 - 2005/10/18/ PY - 2005/04/06/received PY - 2005/09/06/accepted PY - 2005/10/19/pubmed PY - 2006/1/5/medline PY - 2005/10/19/entrez SP - 314 EP - 21 JF - Psychopharmacology JO - Psychopharmacology (Berl) VL - 183 IS - 3 N2 - RATIONALE: It has been proposed that the serotonergic pathway that connects the dorsal raphe nucleus (DRN) to the dorsal periaqueductal gray (DPAG) is implicated in the regulation of escape, a behavior that has been related to panic. OBJECTIVES: We further evaluated this hypothesis by investigating whether intra-DRN injection of the 5-HT(1A) receptor antagonist WAY-100635 changes the escape response of rats submitted to the elevated T-maze. This test also measures inhibitory avoidance, which has been associated with generalized anxiety disorder. We also investigated whether the 5-HT(1A) and 5-HT(2A) receptors in the DPAG mediate the behavioral consequences induced by the injection of WAY-100635 into the DRN. RESULTS: Intra-DRN injection of WAY-100635 facilitated inhibitory avoidance, while impairing escape. The same effect was obtained after intra-DRN injection of the glutamate receptor agonist kainic acid. Preadministration of WAY-100635 into the DPAG counteracted the effect induced by intra-DRN injection of WAY-100635 and of kainic acid on escape, but not on inhibitory avoidance. Preadministration of the preferential 5-HT(2A) receptor antagonist ketanserin into the DPAG abolished the effects of intra-DRN injection of WAY-100635 on both elevated T-maze tasks. CONCLUSION: The results are indicative that 5-HT(1A) autoreceptors in the DRN are under tonic inhibitory influence by endogenous 5-HT. The effects of 5-HT release in the DPAG after intra-DRN injection of WAY-100635 and kainic acid on inhibitory avoidance and escape involve different 5-HT receptor subtypes. Whereas 5-HT(2A) receptors in the DPAG seem to mediate the effect of 5-HT on both behaviors, 5-HT(1A) receptors are only involved in the regulation of escape. SN - 0033-3158 UR - https://www.unboundmedicine.com/medline/citation/16231166/5_HT_1A__and_5_HT_2A__receptors_in_the_rat_dorsal_periaqueductal_gray_mediate_the_antipanic_like_effect_induced_by_the_stimulation_of_serotonergic_neurons_in_the_dorsal_raphe_nucleus_ DB - PRIME DP - Unbound Medicine ER -