Opioid Receptor Blockade Eliminates Mood Effects of Aerobic Gymnastics

The central endogenous opioid system is involved in the modulation of interleukin (IL)-6, an inflammatory cytokine that plays a major role in the acute phase response. The present study evaluates whether specific opioid receptor subtypes are selectively involved in this immunomodulatory action. IL-1 beta was administered either intracerebroventricularly or intraperitoneally at the dose of 400 ng to rats pretreated with the mu-antagonist beta-funaltrexamine, the delta-antagonist naltrindole, or the kappa-antagonist nor-binaltorphimine, each at the doses of 1, 10, and 100 micrograms/rat intracerebroventricularly. Serum IL-6 levels were measured 2 h later. The results show that mu-receptor blockade increases, whereas delta-receptor blockade decreases IL-6 induction, suggesting that the fine tuning exerted by opioids on the immune system may be achieved through a balance of opposing effects. Moreover the three antagonists affect IL-6 induction by central and peripheral IL-1 beta with a similar pattern, indicating that the brain endogenous opioid system plays a general role in the regulation of this cytokine.

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Site-Specific Opioid Receptor Blockade Allows Prepubertal Guinea Pigs to Display Progesterone-Facilitated Lordosis

Hormones and Behavior ◽

10.1006/hbeh.1998.1442 ◽

1998 ◽

Vol 33 (2) ◽

pp. 115-124 ◽

Cited By ~ 4

Author(s):

Deborah H. Olster

Keyword(s):

Opioid Receptor ◽

Guinea Pigs ◽

Receptor Blockade ◽

Site Specific

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Synergistic Interaction between Opioid Receptor Blockade and Alpha-Adrenergic Stimulation on Luteinizing Hormone-Releasing Hormone (LHRH) Secretion in vitro

Neuroendocrinology ◽

10.1159/000125328 ◽

1990 ◽

Vol 51 (2) ◽

pp. 131-138 ◽

Cited By ~ 10

Author(s):

Richard W. Clough ◽

Gloria E. Hoffman ◽

Celia D. Sladek

Keyword(s):

Luteinizing Hormone ◽

Opioid Receptor ◽

Synergistic Interaction ◽

Receptor Blockade ◽

Adrenergic Stimulation ◽

Luteinizing Hormone Releasing Hormone ◽

Releasing Hormone

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Normalization of hyperinsulinemia by chronic opioid receptor blockade in hyperandrogenemic women

Fertility and Sterility ◽

10.1016/j.fertnstert.2006.01.039 ◽

2006 ◽

Vol 86 (3) ◽

pp. 651-657 ◽

Cited By ~ 17

Author(s):

Dijana Hadžiomerović ◽

Bernhard Rabenbauer ◽

Ludwig Wildt

Keyword(s):

Opioid Receptor ◽

Receptor Blockade

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Panicolytic-like effect of µ1-opioid receptor blockade in the inferior colliculus of prey threatened by Crotalus durissus terrificus pit vipers

Journal of Psychopharmacology ◽

10.1177/0269881118822078 ◽

2019 ◽

Vol 33 (5) ◽

pp. 577-588 ◽

Cited By ~ 6

Author(s):

Fabrício Calvo ◽

Rafael Carvalho Almada ◽

Tayllon dos Anjos-Garcia ◽

Luiz Luciano Falconi- Sobrinho ◽

Tatiana Paschoalin-Maurin ◽

...

Keyword(s):

Inferior Colliculus ◽

Opioid Receptor ◽

Panic Attack ◽

Opioid Peptide ◽

Receptor Blockade ◽

Endogenous Opioid ◽

Endogenous Opioid Peptide ◽

Crotalus Durissus Terrificus ◽

Experimental Apparatus ◽

Crotalus Durissus

Background: The endogenous opioid peptide system has been implicated in the neural modulation of fear and anxiety organised by the dorsal midbrain. Furthermore, previous results indicate a fundamental role played by inferior colliculus (IC) opioid mechanisms during the expression of defensive behaviours, but the involvement of the IC µ1-opioid receptor in the modulation of anxiety- and panic attack-related behaviours remains unclear. Using a prey-versus-snake confrontation paradigm, we sought to investigate the effects of µ1-opioid receptor blockade in the IC on the defensive behaviour displayed by rats in a dangerous situation. Methods: Specific pathogen-free Wistar rats were treated with microinjection of the selective µ1-opioid receptor antagonist naloxonazine into the IC at different concentrations (1.0, 3.0 and 5.0 µg/0.2 µL) and then confronted with rattlesnakes ( Crotalus durissus terrificus). The defensive behavioural repertoire, such as defensive attention, flat back approach (FBA), startle, defensive immobility, escape or active avoidance, displayed by rats either during the confrontations with wild snakes or during re-exposure to the experimental context without the predator was analysed. Results: The blockade of µ1-opioid receptors in the IC decreased the expression of both anxiety-related behaviours (defensive attention, FBA) and panic attack-related responses (startle, defensive immobility and escape) during the confrontation with rattlesnakes. A significant decrease in defensive attention was also recorded during re-exposure of the prey to the experimental apparatus context without the predator. Conclusion: Taken together, these results suggest that a decrease in µ1-opioid receptor signalling activity within the IC modulates anxiety- and panic attack-related behaviours in dangerous environments.

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