ABSTRACT
AIM: To investigate the effect of opioid μ receptor on testosterone and its peripheral mechanism. METHODS: Levels of testosterone and testosterone synthetase mRNA in testis plasma and testis homogenate, IGF1 protein and mRNA expression in testis homogenate were detected by intratesticular morphine injection in vivo animal model and treatment of specific μ receptor antagonists and agonists in vitro cultured testis. RESULTS:Serum testosterone level was decreased after testis was injected with morphine [(722.11±121.02) vs. (346.91±75.31) pg/mL; t=7.898, P=0.001]. Testis homogenate testosterone level [(133.61±16.82) vs. (66.56±14.96) pg/mg protein; t=8.941, P=0.001] and expression of testosterone synthetase were decreased. Testis IGF1 level [(7.93±2.13) vs. (2.54±0.74) ng/mg protein, t=7.155, P=0.001] and IGF1 mRNA [(3.22±1.12) vs. (1.66±0.55), t=3.751, P=0.001] expression were decreased in intratesticular morphine injection model. Testosterone level in culture media, IGF1 and expression of testosterone synthetase were decreased after testis was injected with DAMGO in vitro model. And testosterone level, IGF1 and expression of testosterone synthetase were increased after testis was injected with CTOP.CONCLUSION: Morphine acts on opioid μ receptor on the surface of testicular Sertoli cells and inhibits the synthesis of IGF1. It decreases expression of testosterone synthetase Scarb1, Star, 3βHsd, Cyp17α1 and 17βHsd from testicular Leydig cells. which leads to a decrease in testosterone synthesis.
ABSTRACT
The segmental neuronal connection plays an important role in acupoint-target organ specific correlation. The acupoint-target organ correlation includes acupoint-visceral correlation and acupoint-somatic correlation. The acupoint-viscera correlation involves both the primary central (spinal cord) mechanism and the peripheral (dorsal root ganglion, DRG) mechanism implemented by segmental nerve reflex via the spinal cord and axonal reflex via DRG respectively, while the acupoint-somatic correlation mainly involves the axonal reflex.
ABSTRACT
Peripheral mechanisms that induce analgesic effects in manual acupuncture were studied in urethane-anesthetized rats. Unitary extracellular recordings were made from spinal wide dynamic range (WDR) neurons and repetitive electrical stimuli were delivered to the excitatory receptive fields to determine a noxious index. First, the analgesic effects of manual acupuncture and a noxious pinch to the skin (Diffuse Noxious Inhibitory Controls: DNIC) were compared. Second, manual acupuncture was applied to different structures at the acupuncture point, such as the skin, skin plus muscle, and muscle. In a third experiment, the analgesic effects of intramuscular injection of 4.5% NaCl and manual acupuncuture were compared. Manual acupuncture and a noxious pinch exhibited a very similar time course and magnitude of inhibitory effects on C-evoked discharges. As for differential stimulation of the acupuncture point, application of the needle to the skin only was less effective than to the skin plus muscle or the muscle only. Both intramuscular injection of 4.5% NaCl and manual acupuncture reduced C-evoked discharges while injection of isotonic saline produced almost no inhibitory effects. These data suggest that application of manual acupuncture might arouse noxious sensations that result in activating pain inhibitory processes. Moreover, it is thought that excitation of polymodal receptors in the muscle is a critical factor in inducing analgesic effects in manual acupuncture.