Participation of TRPV1 in the activity of the GnRH system in male rats

Abstract

GnRH neuron activity is under the influence of multiple stimuli, including those coming from the endocannabinoid and the immune systems. Since it has been previously suggested that some of the main elements controlling the GnRH pulse generator possess the TRPV1 receptor, the aim of the present study was to evaluate the participation of the hypothalamic TRPV1, through its pharmacological blockade, in the activity of the hypothalamic‐pituitary‐testicular axis in male rats under basal or acute inflammatory conditions. Our hypothesis was based on the idea that the hypothalamic TRPV1 participates in the synthesis of the main neuromodulatory signals controlling GnRH, and therefore the reproductive axis. Our results showed that the hypothalamic TRPV1 blockade induced pro‐inflammatory effects by increasing Tnfα and Il‐1β mRNA hypothalamic levels and inhibited the reproductive axis by affecting Gnrh, Kiss1 and Rfrp3 mRNA levels and decreasing plasma levels of luteinizing hormone and testosterone under basal conditions, without significant additive effects in rats exposed to systemic LPS. Altogether, these results suggest that the hypothalamic TRPV1 receptor participates in the regulation of the GnRH system, probably by modulating immune‐dependent mechanisms.

Insulin-Like Growth Factor 1 Increases GABAergic Neurotransmission to GnRH Neurons via Suppressing the Retrograde Tonic Endocannabinoid Signaling Pathway in Mice

“…Since activity of the 2-AG producing enzyme, diacylglycerol lipase, and therefore, 2-AG production are calcium dependent, the low calcium concentration eventually alters GA-BAergic neurotransmission [64,65]. Importance of TRPV1 in the function of GnRH neurons has also been demonstrated [66]. In addition, relevance of the relationship between TRPV1 and the 2-AG production was revealed in GnRH neurons earlier [54], supporting our present results showing significance of this functional link in the execution of the effect of IGF-1.…”

Hydrosols from Rosmarinus officinalis, Salvia officinalis, and Cupressus sempervirens: Phytochemical Analysis and Bioactivity Evaluation

“…In the colon, they could mediate anti-proliferative and anti-inflammatory effects [ 39 , 40 , 41 ], thus supporting the observed cytotoxic effects on HCT116 cells, especially at the highest tested concentrations. In the hypothalamus, these receptors are mainly involved in neuromodulatory and neuroendocrine effects [ 42 , 43 , 44 , 45 ]. In this regard, we hypothesize that the hydrolates’ neuroprotective effects towards Hypo-E22 could be due, albeit partially, to their intrinsic antiradical effects.…”

Probing Neuro-Endocrine Interactions Through Remote Magnetothermal Adrenal Stimulation

“…Systemic hormone administration in animal studies relies on subcutaneous or intraperitoneal injections, which can be stressful and interfere with the sex hormone effects being investigated. TRP receptors are present in the ovaries, testes, and hypothalamus ( Stein et al, 2004 ; Kunert-Keil et al, 2006 ; Surkin et al, 2020 ). While the thermal effects in this study are attributed mainly to TRPV1 activation, verified also in our previous study, other temperature-sensitive ion channels could be potentially activated, for example TRPV3 with a threshold of 31–39°C ( Broad et al, 2016 ).…”