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.
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 -