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Exposure to Allergen Causes Changes in NTS Neural Activities after Intratracheal Capsaicin Application, in Endocannabinoid Levels and in the Glia Morphology of NTS.

Spaziano G, Luongo L, Guida F, Petrosino S, Matteis M, Palazzo E, Sullo N, de Novellis V, Di Marzo V, Rossi F, Maione S, D'Agostino B - Biomed Res Int (2015)

Bottom Line: Immunohistochemical studies, endocannabinoid, and palmitoylethanolamide quantification in the NTS were also performed.This study provides evidence that allergen sensitization in the NTS induced: (1) increase in the neural firing response to intratracheal capsaicin application, (2) increase of endocannabinoid anandamide and palmitoylethanolamide, a reduction of 2-arachidonoylglycerol levels in the NTS, (3) glial cell activation, and (4) prevention by a Group III metabotropic glutamate receptor activation of neural firing response to intratracheal application of capsaicin in both naïve and sensitized rats.Therefore, normalization of ovalbumin-induced NTS neural sensitization could open up the prospect of new treatments based on the recovery of specific brain nuclei function and for extensive studies on acute or long-term efficacy of selective mGlu ligand, in models of bronchial hyperreactivity.

View Article: PubMed Central - PubMed

Affiliation: Endocannabinoid Research Group, Section of Pharmacology, "L. Donatelli," Department of Experimental Medicine, School of Medicine, Second University of Naples, Via Costantinopoli 16, 80138 Naples, Italy.

ABSTRACT
Allergen exposure may induce changes in the brainstem secondary neurons, with neural sensitization of the nucleus solitary tract (NTS), which in turn can be considered one of the causes of the airway hyperresponsiveness, a characteristic feature of asthma. We evaluated neurofunctional, morphological, and biochemical changes in the NTS of naive or sensitized rats. To evaluate the cell firing activity of NTS, in vivo electrophysiological experiments were performed before and after capsaicin challenge in sensitized or naive rats. Immunohistochemical studies, endocannabinoid, and palmitoylethanolamide quantification in the NTS were also performed. This study provides evidence that allergen sensitization in the NTS induced: (1) increase in the neural firing response to intratracheal capsaicin application, (2) increase of endocannabinoid anandamide and palmitoylethanolamide, a reduction of 2-arachidonoylglycerol levels in the NTS, (3) glial cell activation, and (4) prevention by a Group III metabotropic glutamate receptor activation of neural firing response to intratracheal application of capsaicin in both naïve and sensitized rats. Therefore, normalization of ovalbumin-induced NTS neural sensitization could open up the prospect of new treatments based on the recovery of specific brain nuclei function and for extensive studies on acute or long-term efficacy of selective mGlu ligand, in models of bronchial hyperreactivity.

No MeSH data available.


Related in: MedlinePlus

Effect of vehicle (20% DMSO in ACSF) or capsaicin (300 pg in 20 μL) in naïve (a) and sensitized (b) rats. L-AP4 (4 nmol/rat) (hollow arrow) prevented the capsaicin (full arrow) induced increase in the airway-related NTS neuron ongoing activities. This effect of L-AP4 (4 nmol/rat) was prevented by pretreatment with MSOP (100 nmol/rat) (arrow with lines). Each point represents the mean ± SEM of five rats per group. Values statistically (P value < 0.05) significant versus the respective control were indicated as open symbols.
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fig3: Effect of vehicle (20% DMSO in ACSF) or capsaicin (300 pg in 20 μL) in naïve (a) and sensitized (b) rats. L-AP4 (4 nmol/rat) (hollow arrow) prevented the capsaicin (full arrow) induced increase in the airway-related NTS neuron ongoing activities. This effect of L-AP4 (4 nmol/rat) was prevented by pretreatment with MSOP (100 nmol/rat) (arrow with lines). Each point represents the mean ± SEM of five rats per group. Values statistically (P value < 0.05) significant versus the respective control were indicated as open symbols.

Mentions: The highest doses of L-AP4 (4 nmol/rat) prevented the capsaicin-induced increase in the airway-related NTS neuron activities in both naive and sensitized rats (Figures 3(a) and 3(b)). The effects of L-AP4 (4 nmol/rat) were prevented by pretreatment with MSOP (100 nmol/rat), which per se did not significantly change the airway-related NTS neuron (Figures 3(a) and 3(b)).


Exposure to Allergen Causes Changes in NTS Neural Activities after Intratracheal Capsaicin Application, in Endocannabinoid Levels and in the Glia Morphology of NTS.

Spaziano G, Luongo L, Guida F, Petrosino S, Matteis M, Palazzo E, Sullo N, de Novellis V, Di Marzo V, Rossi F, Maione S, D'Agostino B - Biomed Res Int (2015)

Effect of vehicle (20% DMSO in ACSF) or capsaicin (300 pg in 20 μL) in naïve (a) and sensitized (b) rats. L-AP4 (4 nmol/rat) (hollow arrow) prevented the capsaicin (full arrow) induced increase in the airway-related NTS neuron ongoing activities. This effect of L-AP4 (4 nmol/rat) was prevented by pretreatment with MSOP (100 nmol/rat) (arrow with lines). Each point represents the mean ± SEM of five rats per group. Values statistically (P value < 0.05) significant versus the respective control were indicated as open symbols.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4383154&req=5

fig3: Effect of vehicle (20% DMSO in ACSF) or capsaicin (300 pg in 20 μL) in naïve (a) and sensitized (b) rats. L-AP4 (4 nmol/rat) (hollow arrow) prevented the capsaicin (full arrow) induced increase in the airway-related NTS neuron ongoing activities. This effect of L-AP4 (4 nmol/rat) was prevented by pretreatment with MSOP (100 nmol/rat) (arrow with lines). Each point represents the mean ± SEM of five rats per group. Values statistically (P value < 0.05) significant versus the respective control were indicated as open symbols.
Mentions: The highest doses of L-AP4 (4 nmol/rat) prevented the capsaicin-induced increase in the airway-related NTS neuron activities in both naive and sensitized rats (Figures 3(a) and 3(b)). The effects of L-AP4 (4 nmol/rat) were prevented by pretreatment with MSOP (100 nmol/rat), which per se did not significantly change the airway-related NTS neuron (Figures 3(a) and 3(b)).

Bottom Line: Immunohistochemical studies, endocannabinoid, and palmitoylethanolamide quantification in the NTS were also performed.This study provides evidence that allergen sensitization in the NTS induced: (1) increase in the neural firing response to intratracheal capsaicin application, (2) increase of endocannabinoid anandamide and palmitoylethanolamide, a reduction of 2-arachidonoylglycerol levels in the NTS, (3) glial cell activation, and (4) prevention by a Group III metabotropic glutamate receptor activation of neural firing response to intratracheal application of capsaicin in both naïve and sensitized rats.Therefore, normalization of ovalbumin-induced NTS neural sensitization could open up the prospect of new treatments based on the recovery of specific brain nuclei function and for extensive studies on acute or long-term efficacy of selective mGlu ligand, in models of bronchial hyperreactivity.

View Article: PubMed Central - PubMed

Affiliation: Endocannabinoid Research Group, Section of Pharmacology, "L. Donatelli," Department of Experimental Medicine, School of Medicine, Second University of Naples, Via Costantinopoli 16, 80138 Naples, Italy.

ABSTRACT
Allergen exposure may induce changes in the brainstem secondary neurons, with neural sensitization of the nucleus solitary tract (NTS), which in turn can be considered one of the causes of the airway hyperresponsiveness, a characteristic feature of asthma. We evaluated neurofunctional, morphological, and biochemical changes in the NTS of naive or sensitized rats. To evaluate the cell firing activity of NTS, in vivo electrophysiological experiments were performed before and after capsaicin challenge in sensitized or naive rats. Immunohistochemical studies, endocannabinoid, and palmitoylethanolamide quantification in the NTS were also performed. This study provides evidence that allergen sensitization in the NTS induced: (1) increase in the neural firing response to intratracheal capsaicin application, (2) increase of endocannabinoid anandamide and palmitoylethanolamide, a reduction of 2-arachidonoylglycerol levels in the NTS, (3) glial cell activation, and (4) prevention by a Group III metabotropic glutamate receptor activation of neural firing response to intratracheal application of capsaicin in both naïve and sensitized rats. Therefore, normalization of ovalbumin-induced NTS neural sensitization could open up the prospect of new treatments based on the recovery of specific brain nuclei function and for extensive studies on acute or long-term efficacy of selective mGlu ligand, in models of bronchial hyperreactivity.

No MeSH data available.


Related in: MedlinePlus