NCBI Summary:
The cannabinoid delta-9-tetrahydrocannabinol is the principal psychoactive ingredient of marijuana. The proteins encoded by this gene and the cannabinoid receptor 1 (brain) (CNR1) gene have the characteristics of a guanine nucleotide-binding protein (G-protein)-coupled receptor for cannabinoids. They inhibit adenylate cyclase activity in a dose-dependent, stereoselective, and pertussis toxin-sensitive manner. These proteins have been found to be involved in the cannabinoid-induced CNS effects (including alterations in mood and cognition) experienced by users of marijuana. The cannabinoid receptors are members of family 1 of the G-protein-coupled receptors. [provided by RefSeq, Jul 2008]
General function
Receptor
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Cellular localization
Plasma membrane
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Ovarian function
Luteolysis
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Overactive type 2 cannabinoid receptor induces meiosis in fetal gonads and impairs ovarian reserve. De Domenico E et al. (2017) Type 2 cannabinoid receptor (CB2R) has been proposed to promote in vitro meiotic entry of postnatal male germ cells and to maintain the temporal progression of spermatogenesis in vivo. However, no information is presently available on the role played by CB2R in male and female fetal gonads. Here we show that in vitro pharmacological stimulation with JWH133, a CB2R agonist, induced activation of the meiotic program in both male and female fetal gonads. Upon stimulation, gonocytes initiated the meiotic program but became arrested at early stages of prophase I, while oocytes showed an increased rate of meiotic entry and progression toward more advanced stage of meiosis. Acceleration of meiosis in oocytes was accompanied by a strong increase in the percentage of γ-H2AX-positive pachytene and diplotene cells, paralleled by an increase of TUNEL-positive cells, suggesting that DNA double-strand breaks were not correctly repaired during meiosis, leading to oocyte apoptosis. Interestingly, in vivo pharmacological stimulation of CB2R in fetal germ cells through JWH133 administration to pregnant females caused a significant reduction of primordial and primary follicles in the ovaries of newborns with a consequent depletion of ovarian reserve and reduced fertility in adult life, while no alterations of spermatogenesis in the testis of the offspring were detected. Altogether our findings highlight a pro-meiotic role of CB2R in male and female germ cells and suggest that the use of cannabis in pregnant female might represent a risk for fertility and reproductive lifespan in female offspring.//////////////////
Endocannabinoid 1 and 2 (CB(1); CB(2)) Receptor Agonists Affect Negatively Cow Luteal Function In Vitro. Weems YS et al. Thirty to 40 percent of pregnancies are lost during the first third of pregnancy, which has been hypothesized to be due to inadequate progesterone secretion by the corpus luteum. Loss of luteal progesterone secretion during the estrous cycle is via uterine secretion of prostaglandin F(2)alpha (PGF(2)alpha). Cow luteal tissue secretion of prostaglandins (PG) E (PGE(1)+PGE(2)) and PGF(2)alpha are derived from precursors in membrane phospholipids. Cow luteal tissue secretion of PGE and PGF(2)alpha increased linearly with time in culture with the PGE: ratio being 1:1. PGE(1) or PGE(2) are luteotropic in cows and ewes and antiluteolytic in vitro and in vivo in ewes. Endocannabinoids are also derived from phospholipids and are associated with infertility, presumably by reducing implantation; however, effects of endocannabinoids on luteal function have not been addressed. The objective of this experiment was to determine the effects of endocannabinoid type 1 and 2 receptor agonists and receptor antagonists or a fatty acid amide hydrolase (FAAH; catabolizes endocannabinoids) inhibitor, PGE(1), or PGF(2)alpha on bovine luteal secretion of progesterone, PGE, and PGF(2)alphain vitro. PGE and PGF(2)alpha was increased (P/=0.05) with time in vehicle-treated luteal slices in vitro. Progesterone was increased (PTsutahara NM et al. Thirty to forty percent of ruminant pregnancies are lost during the first third of gestation due to inadequate progesterone secretion. During the estrous cycle, luteinizing hormone (LH) regulates progesterone secretion by small luteal cells (SLC). Loss of luteal progesterone secretion during the estrous cycle is via increased uterine secretion of prostaglandin F(2a) (PGF(2a)) starting on days-12-13 post-estrus in ewes with up to 4-6 pulses per day. Prostaglandin F(2a) is synthesized from arachidonic acid, which is released from phospholipids by phospholipase A2. Endocannabinoids are also derived from phospholipids and are associated with infertility. Endocannabinoid-induced infertility has been postulated to occur primarily via negative effects on implantation. Cannabinoid (CB) type 1(CB1) or type 2 (CB2) receptor agonists and an inhibitor of the enzyme fatty acid amide hydrolase, which catabolizes endocannabinoids, decreased luteal progesterone, prostaglandin E (PGE), and prostaglandin F(2a) (PGF(2a)) secretion by the bovine corpus luteum in vitro by thirty percent. The objectiveof the experiment described herein was to determine whether CB1 or CB2 receptor agonists given in vivo affect circulating progesterone, luteal weights, luteal mRNA for LH receptors, and luteal occupied and unoccupied LH receptors during the estrous cycle of ewes. Treatments were: Vehicle, Methanandamide (CB 1 agonist; METH), or 1-(4-chlorobenzoyl) -5-methoxy-1H-indole-3-acetic acid morpholineamide (CB2 agonist; IMMA). Ewes received randomized treatments on day 10 post-estrus. A single treatment (500g; N=5/treatment group) in a volume of 1ml was given into the interstitial tissue of the ovarian vascular pedicle adjacent to the luteal-containing ovary. Jugular venous blood was collected at 0 hr and every 6 hr through 48 hr for analysis of progesterone by radioimmunoassay (RIA). Corpora lutea were collected at 48 hr, weighed, bisected, and frozen in liquid nitrogen until analysis of unoccupied and occupied LH receptors and mRNA for LH receptors, and. Profiles of jugular venous progesterone, luteal weights, luteal mRNA for LH receptors, and luteal occupied and unoccupied LH receptors were decreased (P< 0.05) by CB1 or CB2 receptor agonists when compared to Vehicle controls. Progesterone in eighty percent of CB1 or CB 2 receptor agonist-treated ewes was decreased (P< 0.05) below one ng/ml by 48 hr post-treatment. It is concluded that stimulation of either CB1 or CB 2 receptors in vivo affected negatively luteal progesterone secretion by decreasing luteal mRNA for LH receptors and also decreasing occupied and unoccupied receptors for LH on luteal membranes. The corpus luteum may be an important site for endocannabinoids to decrease fertility as well as negatively affect implantation, since progesterone is required for implantation.
Expression regulated by
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Ovarian localization
Oocyte, Granulosa, Luteal cells
Comment
Localisation and function of the endocannabinoid system in the human ovary. El-Talatini MR et al. BACKGROUND: Although anandamide (AEA) had been measured in human follicular fluid and is suggested to play a role in ovarian follicle and oocyte maturity, its exact source and role in the human ovary remains unclear. METHODS AND FINDINGS: Immunohistochemical examination of normal human ovaries indicated that the endocannabinoid system was present and widely expressed in the ovarian medulla and cortex with more intense cannabinoid receptor 2 (CB2) than CB1 immunoreactivity in the granulosa cells of primordial, primary, secondary, tertiary follicles, corpus luteum and corpus albicans. The enzymes, fatty acid amide hydrolase (FAAH) and N-acyclphosphatidylethanolamine-phospholipase D (NAPE-PLD), were only found in growing secondary and tertiary follicles and corpora lutea and albicantes. The follicular fluid (FF) AEA concentrations of 260 FF samples, taken from 37 infertile women undergoing controlled ovarian hyperstimulation for in vitro fertilisation and intracytoplasmic sperm injection with embryo transfer, were correlated with ovarian follicle size (P = 0.03). Significantly higher FF AEA concentrations were also observed in mature follicles (1.43+/-0.04 nM; mean+/-SEM) compared to immature follicles (1.26+/-0.06 nM), P = 0.0142 and from follicles containing morphologically assessed mature oocytes (1.56+/-0.11 nM) compared to that containing immature oocytes (0.99+/-0.09 nM), P = 0.0011. ROC analysis indicated that a FF AEA level of 1.09 nM could discriminate between mature and immature oocytes with 72.2% sensitivity and 77.14% specificity, whilst plasma AEA levels and FF AEA levels on oocyte retrieval day were not significantly different (P = 0.23). CONCLUSIONS: These data suggest that AEA is produced in the ovary, is under hormonal control and plays a role in folliculogenesis, preovulatory follicle maturation, oocyte maturity and ovulation.
Temporal and Spatial Distribution of the Cannabinoid Receptors (CB(1), CB(2)) and Fatty Acid Amide Hydroxylase in the Rat Ovary. Bagavandoss P et al. Although the effects of Delta(9)-tetrahydrocannabinol (THC) on ovarian physiology have been known for many decades, its mechanism of action in the rat ovary remains poorly understood. The effects of THC and endocannabinoids on many cell types appear to be mediated through the G-protein-coupled CB(1) and CB(2) receptors. Evidence also suggests that the concentration of the endocannabinoid anandamide is regulated by cellular fatty acid amide hydrolase (FAAH). Therefore, we examined the rat ovary for the presence of CB(1) and CB(2) receptors and FAAH. The CB(1) receptor was present in the ovarian surface epithelium (OSE), the granulosa cells of antral follicles, and the luteal cells of functional corpus luteum (CL). The granulosa cells of small preantral follicles, however, did not express the CB(1) receptor. Western analysis also demonstrated the presence of a CB(1) receptor. In both preantral and antral follicles, the CB(2) receptor was detected only in the oocytes. In the functional CL, the CB(2) receptor was detected in the luteal cells. FAAH was codistributed with CB(2) receptor in both oocytes and luteal cells. FAAH was also present in the OSE, subepithelial cords of the tunica albuginea (TA) below the OSE, and in cells adjacent to developing preantral follicles. Western analysis also demonstrated the presence of FAAH in oocytes of both preantral and antral follicles. Our observations provide potential explanation for the effects of THC on steroidogenesis in the rat ovary observed by earlier investigators and a role for FAAH in the regulation of ovarian anandamide. Anat Rec 293:1425-1432, 2010. (c) 2010 Wiley-Liss, Inc.
Follicle stages
Primordial, Primary, Secondary, Antral, Preovulatory, Corpus luteum