Related Experiment Video
Updated: May 1, 2026

Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Interactions of morphine and Peptide 234 on mean plasma testosterone concentration
Fariba Mahmoudi1, Homayoun Khazali1, Mahyar Janahmadi2
1Department of Animal Sciences,Faculty of Biological Sciences, Shahid Beheshti University, Tehran, IR Iran.
Background:
Kisspeptin-GPR54 system stimulates the hypothalamus-pituitary-gonadal (HPG) axis; dysfunction of the gene encoding the GPR54 receptor causes hypogonadism and infertility. Opioid peptides inhibit the reproductive axis. Peptide 234 is a GPR54 receptor antagonist and blocks the stimulatory effects of kisspeptin on HPG axis.
Objectives:
Interactions of morphine, kisspeptin and peptide 234 on mean plasma testosterone concentration was investigated in rats. .
Materials And Methods:
In the present experimental study, seventy male Wistar rats in 14 groups (n = 5 in each group) received saline, different doses of kisspeptin (100 pmol, 1 or 3 nmol, Intracerebroventricular (ICV)), P234 (1 or 2.5 nmol) or Co- administration of kisspeptin, P234, morphine and naloxone at 09:00 - 09:30 am. In the co-administrated groups, kisspeptin was injected at 15 min following P234, morphine or naloxone injections. Blood samples were collected 60 min following injections. Plasma testosterone concentration was measured using the rat testosterone ELISA kit.
Results:
Injections of kisspeptin (1 or 3 nmol) significantly increased the mean testosterone concentration compared to saline. Injection of different doses of P234 (1 or 2.5nmol) did not significantly decrease mean testosterone compared to saline. Co-administration of kisspeptin and different doses of P234 significantly decreased mean testosterone concentration compared to the kisspeptin group. Co-administration of P234/morphine or P234/naloxone significantly decreased mean testosterone concentration compared to kisspeptin/saline, kisspeptin/morphine or kisspeptin/ naloxone groups.
Conclusions:
Morphine and kisspeptin/GPR54 signaling pathway may interact with each other to control the hypothalamic-pituitary-gonadal axis.
More Related Videos
09:54Combining Laser Capture Microdissection and Microfluidic qPCR to Analyze Transcriptional Profiles of Single Cells: A Systems Biology Approach to Opioid Dependence
Published on: March 8, 2020
04:11A Conditioned Place Preference Protocol for Measuring Incubation of Craving in Rats
Published on: November 6, 2018
Related Concept Videos
Opioid Analgesics: Morphine and Other Natural Cogeners
Opioid Analgesics: Synthetic and Semisynthetic Opioids
Opioid Receptors: Overview
Analgesia and Pain Management
Drug-Receptor Interaction: Antagonist
Antagonists can be classified as competitive or noncompetitive based on their...
Agonism and Antagonism: Quantification
To quantify these effects, researchers use a dose-response curve, which provides valuable information about the potency and efficacy of a drug. Potency refers to...