Early cannabinoid exposure influences neuroendocrine and reproductive functions in male mice: I. Prenatal exposure

Cannabidiol Exposure During Gestation Leads to Adverse Cardiac Outcomes Early in Postnatal Life in Male Rat Offspring

Introduction: Studies indicate that ∼7% of pregnant individuals in North America consume cannabis in pregnancy. Pre-clinical studies have established that maternal exposure to Δ9-tetrahydrocannabinol (THC; major psychoactive component in cannabis) leads to fetal growth restriction and impaired cardiac function in offspring. However, the effects of maternal exposure to cannabidiol (CBD; major non-euphoric constituent) on cardiac outcomes in offspring remain unknown. Therefore, our objective is to investigate the functional and underlying molecular impacts in the hearts of offspring exposed to CBD in pregnancy. Methods: Pregnant Wistar rats were exposed to either 3 or 30 mg/kg CBD or vehicle control i.p. daily from gestational day 6 to term. Echocardiography was used to assess cardiac function in male and female offspring at postnatal day (PND) 21. Furthermore, quantitative polymerase chain reaction (qPCR), immunoblotting, and bulk RNA-sequencing (RNA-seq) were performed on PND21 offspring hearts. Results: Despite no differences in the heart-to-body weight ratio, both doses of CBD led to reduced cardiac function exclusively in male offspring at 3 weeks of age. Underlying this, significant alterations in the expression of the endocannabinoid system (ECS; e.g., decreased cannabinoid receptor 2) were observed. In addition, bulk RNA-seq data demonstrated transcriptional pathways significantly enriched in mitochondrial function/metabolism as well as development. Conclusion: Collectively, we demonstrated for the first time that gestational exposure to CBD, a constituent perceived as safe, leads to early sex-specific postnatal cardiac deficits and alterations in the cardiac ECS in offspring.

Cannabidiol reduces intraventricular hemorrhage brain damage, preserving myelination and preventing blood brain barrier dysfunction in immature rats

Intraventricular hemorrhage (IVH) is an important cause of long-term disability in extremely preterm infants, with no current treatment. This study assessed the potential neuroprotective effects of cannabidiol (CBD) in an IVH model using immature rats. IVH was induced in 1-day-old (P1) Wistar rats by left periventricular injection of Clostridial collagenase. Some rats received CBD prenatally (10 ​mg/kg i.p. to the dam) and then 5 ​mg/kg i.p. 6, 30 and 54 ​h after IVH (IVH+CBD, n ​= ​30). Other IVH rats received vehicle (IVH+VEH, n ​= ​34) and vehicle-treated non-IVH rats served as controls (SHM, n ​= ​29). Rats were humanely killed at P6, P14 or P45. Brain damage (motor and memory performance, area of damage, Lactate/N-acetylaspartate ratio), white matter injury (ipsilateral hemisphere and corpus callosum volume, oligodendroglial cell density and myelin basic protein signal), blood-brain barrier (BBB) integrity (Mfsd2a, occludin and MMP9 expression, gadolinium leakage), inflammation (TLR4, NFκB and TNFα expression, infiltration of pro-inflammatory cells), excitotoxicity (Glutamate/N-acetylspartate ratio) and oxidative stress (protein nitrosylation) were then evaluated. CBD prevented the long-lasting motor and cognitive consequences of IVH, reduced brain damage in the short- and long-term, protected oligodendroglial cells preserving adequate myelination and maintained BBB integrity. The protective effects of CBD were associated with the modulation of inflammation, excitotoxicity and oxidative stress. In conclusion, in immature rats, CBD reduced IVH-induced brain damage and its short- and long-term consequences, showing robust and pleiotropic neuroprotective effects. CBD is a potential candidate to ameliorate IVH-induced immature brain damage.

Toxicological Evaluation and Pain Assessment of Four Minor Cannabinoids Following 14-Day Oral Administration in Rats

Introduction: Despite growing consumer interest and market availability, the safety of minor cannabinoids, generally present in low concentrations in Cannabis sativa L., is not well understood. Materials and Methods: Cannabichromene (CBC; 3.2, 10, 17, 22, 32, or 100 mg/kg-bw/day), cannabinol (CBN; 1, 3.2, 10, 17, 32, or 100 mg/kg-bw/day), delta-8-tetrahydrocannabinol (D8-THC; 0.32, 1, 3.2, or 10 mg/kg-bw/day), tetrahydrocannabivarin (THCV; 3.2, 10, 17, 22, 32, or 100 mg/kg-bw/day), and vehicle (medium-chain triglyceride oil) preparations were administered via oral gavage once daily for 14 days to Sprague Dawley rats. Changes in behavior, body weight, food consumption, clinical pathology, organ weights, body temperature, and thermal pain sensitivity (tail flick assay) were assessed. Select organ tissues were collected at terminal necropsy and fixed for histopathological examination. Results: No treatment-related deaths were observed throughout the study, and cannabinoids were generally well tolerated. While some significant trends in body weight differences from controls (increases and decreases) were observed, these occurred independently of food consumption. Overall, differences in serum chemistry and hematology parameters between cannabinoid groups and their respective control groups were considered to occur due to biological variation among rats. No treatment-related gross abnormalities were observed in examined organs. Significant changes in absolute and relative organ weights occurred primarily in males and were generally of negligible magnitude. There were no biologically significant histopathological observations. While pain tolerance was significantly improved in animals treated with D8-THC (3.2 and 10 mg/kg-bw/day, day 14), results across minor cannabinoids were inconsistent and warrant further study. Conclusion: Minor cannabinoids were well tolerated across 14 days of daily oral administration at the doses assessed. Modest, dose-dependent trends in relative organ weights and serum chemistry parameters warrant exploration at higher oral doses. These data will assist in dose selection for future studies investigating the long-term safety and effects of CBC, CBN, D8-THC, and THCV.

Reproductive and developmental toxicity evaluation of cannabidiol

An important data gap in determining a safe level of cannabidiol (CBD) intake for consumer use is determination of CBD's potential to cause reproductive or developmental toxicity. We conducted an OECD Test Guideline 421 GLP-compliant study in rats, with extended postnatal dosing and hormone analysis, where hemp-derived CBD isolate (0, 30, 100, or 300 mg/kg-bw/d) was administered orally. Treatment-related mortality, moribundity, and decreased body weight and food consumption were observed in high-dose F₀ adult animals, consistent with severe maternal toxicity. No effects were observed on testosterone concentrations, F₀ reproductive performance, or reproductive organs. Hepatocellular hypertrophy in the 100- and 300 mg/kg-bw/day groups correlated with hypertrophy/hyperplasia in the thyroid gland and changes in mean thyroid hormone concentrations in F₀ animals. Mean gestation length was unaffected; however, total litter loss for two females and dystocia for two additional females in the high-dose group occurred. Other developmental effects were limited to lower mean pup weights in the 300 mg/kg-bw/d group than those of controls. The following NOAELs were identified for CBD isolate based on this study: 100 mg/kg-bw/d for F₀ systemic toxicity and female reproductive toxicity, 300 mg/kg-bw/d for F₀ male reproductive toxicity, and 100 mg/kg-bw/d for F₁ neonatal and F₁ generation toxicity.

Animal evidence considered in determination of cannabis smoke and Δ9 -tetrahydrocannabinol as causing reproductive toxicity (developmental endpoint); Part I. somatic development

OBJECTIVES

On December 11, 2019, California's Developmental and Reproductive Toxicant Identification Committee (DARTIC) met to consider the addition of cannabis smoke and Δ⁹ -THC to the Proposition 65 list as causing reproductive toxicity (developmental endpoint). As the lead state agency for implementing Proposition 65, the Office of Environmental Health Hazard Assessment (OEHHA) reviewed and summarized the relevant scientific literature in the form of a hazard identification document (HID). Here we provide reviews based on the HID: shortened, revised, and reformatted for a larger audience.

METHODS

While the HID included both human and animal data, this set of three reviews will highlight the animal-derived data pertaining to somatic development (Part I), neurodevelopmental effects (Part II), and proposed neurodevelopmental mechanisms of action (Part III).

RESULTS

Endogenous cannabinoids (eCBs) and their receptors serve many critical functions in normal development. Δ⁹ -THC can interfere with these functions. Mechanistic studies employed techniques including: blocking Δ⁹ -THC binding to endocannabinoid (EC) receptors, inhibiting Δ⁹ -THC metabolism, and/or using animals expressing knockout mutations of EC receptors. Apical somatic effects of cannabis smoke or Δ⁹ -THC reported in whole animal studies included decreases in offspring viability and growth. Mechanistic studies discussed in Part I focused on Δ⁹ -THC effects on early embryos and implantation, immune development, and bone growth.

CONCLUSIONS

In reaching its decision to list cannabis and Δ⁹ -THC as a developmental toxicant under California's Proposition 65, the DARTIC considered biological plausibility and the consistency of mechanistic information with effects reported in human and whole animal studies.

Statement on safety of cannabidiol as a novel food: data gaps and uncertainties

The European Commission has determined that cannabidiol (CBD) can be considered as a novel food (NF), and currently, 19 applications are under assessment at EFSA. While assessing these, it has become clear that there are knowledge gaps that need to be addressed before a conclusion on the safety of CBD can be reached. Consequently, EFSA has issued this statement, summarising the state of knowledge on the safety of CBD consumption and highlighting areas where more data are needed. Literature searches for both animal and human studies have been conducted to identify safety concerns. Many human studies have been carried out with Epidyolex^®, a CBD drug authorised to treat refractory epilepsies. In the context of medical conditions, adverse effects are tolerated if the benefit outweighs the adverse effect. This is, however, not acceptable when considering CBD as a NF. Furthermore, most of the human data referred to in the CBD applications investigated the efficacy of Epidyolex (or CBD) at therapeutic doses. No NOAEL could be identified from these studies. Given the complexity and importance of CBD receptors and pathways, interactions need to be taken into account when considering CBD as a NF. The effects on drug metabolism need to be clarified. Toxicokinetics in different matrices, the half‐life and accumulation need to be examined. The effect of CBD on liver, gastrointestinal tract, endocrine system, nervous system and on psychological function needs to be clarified. Studies in animals show significant reproductive toxicity, and the extent to which this occurs in humans generally and in women of child‐bearing age specifically needs to be assessed. Considering the significant uncertainties and data gaps, the Panel concludes that the safety of CBD as a NF cannot currently be established.

Maternal-fetal transmission of delta-9-tetrahydrocannabinol (THC) and its metabolites following inhalation and injection exposure during pregnancy in rats

Cannabis use during pregnancy has increased over the past few decades, with recent data indicating that, in youth and young adults especially, up to 22% of people report using cannabis during pregnancy. Animal models provide the ability to study prenatal cannabis exposure (PCE) with control over timing and dosage; however, these studies utilize both injection and inhalation approaches. While it is known that Δ9-tetrahydrocannabinol (THC; primary psychoactive component of cannabis) can cross the placenta, examination of the transmission and concentration of THC and its metabolites from maternal blood into the placenta and fetal brain remains relatively unknown, and the influence of route of administration has never been examined. Pregnant female rats were exposed to either vaporized THC-dominant cannabis extract for pulmonary consumption or subcutaneous injection of THC repeatedly during the gestational period. Maternal blood, placenta, and fetal brains were collected following the final administration of THC for analysis of THC and its metabolites, as well as endocannabinoid concentrations, through mass spectrometry. Both routes of administration resulted in the transmission of THC and its metabolites in placenta and fetal brain. Repeated exposure to inhaled THC vapor resulted in fetal brain THC concentrations that were about 30% of those seen in maternal blood, whereas repeated injections resulted in roughly equivalent concentrations of THC in maternal blood and fetal brain. Neither inhalation nor injection of THC during pregnancy altered fetal brain endocannabinoid concentrations. Our data provide the first characterization of maternal-fetal transmission of THC and its metabolites following both vaporized delivery and injection routes of administration. These data are important to establish the maternal-fetal transmission in preclinical injection and inhalation models of PCE and may provide insight into predicting fetal exposure in human studies.

Effects of Cannabinoid Exposure during Neurodevelopment on Future Effects of Drugs of Abuse: A Preclinical Perspective

The endocannabinoid system plays a central role in the earliest stages of embryonic, postnatal and adolescent neurodevelopment. Aberrant activity of this system at key developmental phases has been shown to affect neural development. The aim of this review is to synthesise and analyse preclinical insights within rodent populations, focusing on the effects that perinatal (embryonic, gestational and early postnatal developmental stages) and adolescent (postnatal day 21–60) cannabinoid exposure impose across time on the subsequent activity of various drugs of abuse. Results in rodents show that exposure to cannabinoids during the perinatal and adolescent period can lead to multifaceted behavioural and molecular changes. In the perinatal period, significant effects of Δ⁹-THC exposure on subsequent opiate and amphetamine reward-related behaviours were observed primarily in male rodents. These effects were not extended to include cocaine or alcohol. In adolescence, various cannabinoid agonists were used experimentally. This array of cannabinoids demonstrated consistent effects on opioids across sex. In contrast, no significant effects were observed regarding the future activity of amphetamines and cocaine. However, these studies focused primarily on male rodents. In conclusion, numerous gaps and limitations are apparent in the current body of research. The sparsity of studies analysing the perinatal period must be addressed. Future research within both periods must also focus on delineating sex-specific effects, moving away from a male-centric focus. Studies should also aim to utilise more clinically relevant cannabinoid treatments.

Cannabis constituents reduce seizure behavior in chemically-induced and scn1a-mutant zebrafish

Current antiepileptic drugs (AEDs) are undesirable for many reasons including the inability to reduce seizures in certain types of epilepsy, such as Dravet syndrome (DS) where in one-third of patients does not respond to current AEDs, and severe adverse effects that are frequently experienced by patients. Epidiolex, a cannabidiol (CBD)-based drug, was recently approved for treatment of DS. While Epidiolex shows great promise in reducing seizures in patients with DS, it is used in conjunction with other AEDs and can cause liver toxicity. To investigate whether other cannabis-derived compounds could also reduce seizures, the antiepileptic effects of CBD, Δ9-tetrahydrocannabinol (THC), cannabidivarin (CBDV), cannabinol (CBN), and linalool (LN) were compared in both a chemically-induced (pentylenetetrazole, PTZ) and a DS (scn1Lab^-/-) seizure models. Zebrafish (Danio rerio) that were either wild-type (Tupfel longfin) or scn1Lab^-/- (DS) were exposed to CBD, THC, CBDV, CBN, or LN for 24 h from 5 to 6 days postfertilization. Following exposure, total distance traveled was measured in a ViewPoint Zebrabox to determine if these compounds reduced seizure-like activity. Cannabidiol (0.6 and 1 μM) and THC (1 and 4 μM) significantly reduced PTZ-induced total distance moved. At the highest THC concentration, the significant reduction in PTZ-induced behavior was likely the result of sedation as opposed to antiseizure activity. In the DS model, CBD (0.6 μM), THC (1 μM), CBN (0.6 and 1 μM), and LN (4 μM) significantly reduced total distance traveled. Cannabinol was the most effective at reducing total distance relative to controls. In addition to CBD, other cannabis-derived compounds showed promise in reducing seizure-like activity in zebrafish. Specifically, four of the five compounds were effective in the DS model, whereas in the PTZ model, only CBD and THC were, suggesting a divergence in the mode of action among the cannabis constituents.

Developmental exposure to Δ9-tetrahydrocannabinol (THC) causes biphasic effects on longevity, inflammation, and reproduction in aged zebrafish (Danio rerio)

Increased availability of cannabis and cannabinoid-containing products necessitates the need for an understanding of how these substances influence aging. In this study, zebrafish (Danio rerio) were exposed to different concentrations of THC (0.08, 0.4, 2 μM) during embryonic-larval development and the effects on aging were measured 30 months later and in the offspring of the exposed fish (F1 generation). Exposure to 0.08 μM THC resulted in increased male survival at 30 months of age. As the concentration of THC increased, this protective effect was lost. Treatment with the lowest concentration of THC also significantly increased egg production, while higher concentrations resulted in impaired fecundity. Treatment with the lowest dose of THC significantly reduced wet weight, the incidence of kyphosis, and the expression of several senescence and inflammatory markers (p16ink4ab, tnfα, il-1β, il-6, pparα and pparγ) in the liver, but not at higher doses indicating a biphasic or hormetic effect. Exposure to THC did not affect the age-related reductions in locomotor behavior. Within the F1 generation, many of these changes were not observed. However, the reduction in fecundity due to THC exposure was worse in the F1 generation because offspring whose parents received high dose of THC were completely unable to reproduce. Together, our results demonstrate that a developmental exposure to THC can cause significant effects on longevity and healthspan of zebrafish in a biphasic manner.

Developmental exposure to cannabidiol (CBD) alters longevity and health span of zebrafish (Danio rerio)

Consumption of cannabinoid-containing products is on the rise, even during pregnancy. Unfortunately, the long-term, age-related consequences of developmental cannabidiol (CBD) exposure remain largely unknown. This is a critical gap given the established Developmental Origins of Health and Disease (DOHaD) paradigm which emphasizes that stressors, like drug exposure, early in life can instigate molecular and cellular changes that ultimately lead to adverse outcomes later in life. Thus, we exposed zebrafish (Danio rerio) to varying concentrations of CBD (0.02, 0.1, 0.5 μM) during larval development and assessed aging in both the F0 (exposed generation) and their F1 offspring 30 months later. F0 exposure to CBD significantly increased survival (~ 20%) and reduced size (wet weight and length) of female fish. While survival was increased, the age-related loss of locomotor function was unaffected and the effects on fecundity varied by sex and dose. Treatment with 0.5 μM CBD significantly reduced sperm concentration in males, but 0.1 μM increased egg production in females. Similar to other model systems, control aged zebrafish exhibited increased kyphosis as well as increased expression markers of senescence, and inflammation (p16^ink4ab, tnfα, il1b, il6, and pparγ) in the liver. Exposure to CBD significantly reduced the expression of several of these genes in a dose-dependent manner relative to the age-matched controls. The effects of CBD on size, gene expression, and reproduction were not reproduced in the F1 generation, suggesting the influence on aging was not cross-generational. Together, our results demonstrate that developmental exposure to CBD causes significant effects on the health and longevity of zebrafish.

The effects of cannabidiol on male reproductive system: A literature review

Cannabidiol (CBD) is one of the most abundant phytocannabinoids present in the plant Cannabis sativa (marijuana). There have been several studies of CBD in the last few decades, mainly focused on its neuroprotective properties, particularly after the identification of the endocannabinoid system and its participation in the central nervous system. On the other hand, the peripheral effects of CBD, particularly on reproductive physiology, were also evidenced. A narrative review was conducted using the PubMed database to identify studies that analyzed the pharmacological effects of CBD on the male reproductive system of vertebrates and invertebrates. Thirty-two citations (in vivo and in vitro) were identified. Among the vertebrates, the studies were carried out with men, monkeys, rats and mice. Studies with invertebrates are centered exclusively on the sea urchin. The CBD treatment periods include mostly acute and subacute evaluations. Exposure to CBD is associated with a reduction in mammalian testis size, the number of germ and Sertoli cells in spermatogenesis, fertilization rates, and plasma concentrations of hypothalamic, pituitary and gonadal hormones. Moreover, chronic doses of CBD have impaired sexual behavior in mice. From the studies identified in this review, it is possible to conclude that CBD has negative effects on the reproductive system of males. However, knowledge is still limited, and additional research is required to elucidate fully the mechanisms of action, as well as the reversibility of CBD effects on the reproductive system.

Multigenerational consequences of early-life cannabinoid exposure in zebrafish

While Δ⁹-tetrahydrocannabinol (THC) has been widely studied in the realm of developmental and reproductive toxicology, few studies have investigated potential toxicities from a second widely used cannabis constituent, cannabidiol (CBD). CBD is popularized for its therapeutic potential for reducing seizure frequencies in epilepsy. This study investigated developmental origins of health and disease (DOHaD) via multigenerational gene expression patterns, behavior phenotypes, and reproductive fitness of a subsequent F1 following an F0 developmental exposure of zebrafish (Danio rerio) to THC (0.024, 0.12, 0.6 mg/L; 0.08, 0.4, 2 μM) or CBD (0.006, 0.03, 0.15 mg/L; 0.02, 0.1, 0.5 μM). Embryonic exposure at these concentrations did not cause notable morphological abnormalities in either F0 or F1 generations. However, during key developmental stages (14, 24, 48, 72, and 96 h post fertilization) THC and CBD caused differential expression of c-fos, brain-derived neurotrophic factor (bdnf), and deleted-in-azoospermia like (dazl), while in F1 larvae only CBD differentially expressed dazl. Larval photomotor behavior was reduced (F0) or increased (F1) by THC exposure, while CBD had no effect on F0 larvae, but decreased activity in the unexposed F1 larvae. These results support our hypothesis of cannabinoid-related developmental neurotoxicity. As adults, F0 fecundity was reduced, but it was not in F1 adults. Conversely, in the adult open field test there were no significant effects in F0 fish, but a significant reduction in the time in periphery was seen in F1 fish from the highest THC exposure group. The results highlight the need to consider long-term ramifications of early-life exposure to cannabinoids.

Long-term consequences of perinatal and adolescent cannabinoid exposure on neural and psychological processes

Marihuana is the most widely consumed illicit drug, even among adolescents and pregnant women. Given the critical developmental processes that occur in the adolescent and fetal nervous system, marihuana consumption during these stages may have permanent consequences on several brain functions in later adult life. Here, we review what is currently known about the long-term consequences of perinatal and adolescent cannabinoid exposure. The most consistent findings point to long-term impairments in cognitive function that are associated with structural alterations and disturbed synaptic plasticity. In addition, several neurochemical modifications are also evident after prenatal or adolescent cannabinoid exposure, especially in the endocannabinoid, glutamatergic, dopaminergic and opioidergic systems. Important sexual dimorphisms are also evident in terms of the long-lasting effects of cannabinoid consumption during pregnancy and adolescence, and cannabinoids possibly have a protective effect in adolescents who have suffered traumatic life challenges, such as maternal separation or intense stress. Finally, we suggest some future research directions that may encourage further advances in this exciting field.

Type-1 cannabinoid receptors reduce membrane fluidity of capacitated boar sperm by impairing their activation by bicarbonate

BACKGROUND

Mammalian spermatozoa acquire their full fertilizing ability (so called capacitation) within the female genital tract, where they are progressively exposed to inverse gradients of inhibiting and stimulating molecules.

METHODOLOGY/PRINCIPAL FINDINGS

In the present research, the effect on this process of anandamide, an endocannabinoid that can either activate or inhibit cannabinoid receptors depending on its concentration, and bicarbonate, an oviductal activatory molecule, was assessed, in order to study the role exerted by the type 1 cannabinoid receptor (CB1R) in the process of lipid membrane remodeling crucial to complete capacitation. To this aim, boar sperm were incubated in vitro under capacitating conditions (stimulated by bicarbonate) in the presence or in the absence of methanandamide (Met-AEA), a non-hydrolysable analogue of anandamide. The CB1R involvement was studied by using the specific inhibitor (SR141716) or mimicking its activation by adding a permeable cAMP analogue (8Br-cAMP). By an immunocytochemistry approach it was shown that the Met-AEA inhibits the bicarbonate-dependent translocation of CB1R from the post-equatorial to equatorial region of sperm head. In addition it was found that Met-AEA is able to prevent the bicarbonate-induced increase in membrane disorder and the cholesterol extraction, both preliminary to capacitation, acting through a CB1R-cAMP mediated pathway, as indicated by MC540 and filipin staining, EPR spectroscopy and biochemical analysis on whole membranes (CB1R activity) and on membrane enriched fraction (C/P content and anisotropy).

CONCLUSIONS/SIGNIFICANCE

Altogether, these data demonstrate that the endocannabinoid system strongly inhibits the process of sperm capacitation, acting as membrane stabilizing agent, thus increasing the basic knowledge on capacitation-related signaling and potentially opening new perspectives in diagnostics and therapeutics of male infertility.

Developmental consequences of perinatal cannabis exposure: behavioral and neuroendocrine effects in adult rodents

RATIONALE

Cannabis is the most commonly used illicit drug among pregnant women. Since the endocannabinoid system plays a crucial role in brain development, maternal exposure to cannabis derivatives might result in long-lasting neurobehavioral abnormalities in the exposed offspring. It is difficult to detect these effects, and their underlying neurobiological mechanisms, in clinical cohorts, because of their intrinsic methodological and interpretative issues.

OBJECTIVES

The present paper reviews relevant rodent studies examining the long-term behavioral consequences of exposure to cannabinoid compounds during pregnancy and/or lactation.

RESULTS

Maternal exposure to even low doses of cannabinoid compounds results in atypical locomotor activity, cognitive impairments, altered emotional behavior, and enhanced sensitivity to drugs of abuse in the adult rodent offspring. Some of the observed behavioral abnormalities might be related to alterations in stress hormone levels induced by maternal cannabis exposure.

CONCLUSIONS

There is increasing evidence from animal studies showing that cannabinoid drugs are neuroteratogens which induce enduring neurobehavioral abnormalities in the exposed offspring. Several preclinical findings reviewed in this paper are in line with clinical studies reporting hyperactivity, cognitive impairments and altered emotionality in humans exposed in utero to cannabis. Conversely, genetic, environmental and social factors could also influence the neurobiological effects of early cannabis exposure in humans.

Corticosterone administration to rat pups, but not maternal separation, affects sexual maturation and glucocorticoid receptor immunoreactivity in the testis

Prenatal stress strongly affects sexual dimorphism of male rats. Much less information is instead available on the effects of postnatal stress on sexual maturation during the so-called stress hyporesponsive period (SHRP). For this reason, we compared corticosterone-treated (CS; 10 mg/kg sc, suspended in sesame oil) or maternally separated pups (MS; 5 h/day in the first week of life) with control rats. Control and MS pups also received sesame oil injections. The effects of these procedures on physical development (body weight and eye opening), sexual maturation [anogenital distance, testis weight, 3beta-hydroxysteroid dehydrogenase/(Delta5-4) (3betaHSD) isomerase activity and time to testis descent] and glucocorticoid receptor (GR) immunoreactivity in the testis were examined. Corticosterone treatment significantly (P<.05) advanced testis descent and increased testis weight and 3betaHSD activity at puberty. In addition, adult CS rats presented higher levels of GR immunoreactivity in testicular tubules when compared to control and MS rats. No differences were found between control and MS rats. On this basis, we propose that the silencing of adrenocortical function during the SHRP could be finalized to preserve sexual maturation from the influence of glucocorticoid effects. As SHRP is unique to rodents, this phenomenon could be related to their successful reproductive strategy.

Elevated plasma norepinephrine after in utero exposure to cocaine and marijuana

OBJECTIVE

To compare plasma catecholamine concentrations between cocaine-exposed and unexposed term newborns and to determine the relationship between plasma catecholamines and newborn behavior.

METHODS

Forty-six newborn infants participating in a prospective study of the neonatal and long-term effects of prenatal cocaine exposure were studied. Based on maternal self-report, maternal urine screening, and infant meconium analysis, 24 infants were classified as cocaine-exposed and 22 as unexposed. Between 24 and 72 hours postpartum, plasma samples for norepinephrine (NE), epinephrine, dopamine, and dihydroxyphenylalanine analysis were obtained. The Neonatal Behavioral Assessment Scale was administered at 1 to 3 days of age and at 2 weeks of age by examiners masked to the drug exposure status of the newborns.

RESULTS

The cocaine-exposed newborns had increased plasma NE concentrations when compared to the unexposed infants (geometric mean, 923 pg/mL vs 667 pg/mL). There were no significant differences in plasma epinephrine, dopamine, or dihydroxyphenylalanine concentrations. Analysis for the effect of potential confounding variables revealed that maternal marijuana use was also associated with increased plasma NE, although birth weight, gender, and maternal use of alcohol or cigarettes were not. Geometric mean plasma NE was 1164 pg/mL in those infants with in utero exposure to both cocaine and marijuana compared to 812 pg/mL in those exposed to only cocaine and 667 pg/mL in those exposed to neither. Among the cocaine-exposed infants, plasma NE concentration correlated with an increased score for the depressed cluster (r = .53) and a decreased score for the orientation cluster (r = -.43) of the Neonatal Behavioral Assessment Scale administered at 1 to 3 days of age. Adjusting for marijuana exposure had no effect on these relationships between plasma NE and the depressed and orientation clusters.

CONCLUSION

Plasma NE is increased in newborns exposed to cocaine and marijuana. Increased plasma NE is associated with selected neurobehavioral disturbances among cocaine exposed infants at 1 to 3 days of life but not at 2 weeks.

Effects of prenatal exposure to delta-9-tetrahydrocannabinol on reproductive, endocrine and immune parameters of male and female rat offspring

The effects of prenatal THC administration, given during the third week of gestation in rats, on the reproductive, endocrine and immune systems of the adult offspring were examined. THC treatment blocked the surge of testosterone which occurs in the male rat fetus on gestation day 18. Moreover, when copulatory parameters were measured in adult male offspring, males that had been exposed to THCin utero exhibited an increased latency to mount (THC: 245±49vs vehicle: 99±12 sec) and none of the males ejaculated. Female rats exposed to THCin utero, exhibited an increased incidence of irregular estrous cycles and the number of females exhibiting lordosis behavior was reduced when compared to vehicle controls. Hormone analyses revealed that prolactin levels were significantly lower in the THC-vs vehicle-exposed male (THC: 5.2±0.4vs vehicle: 8.4±0.6 ng/ml) and female offspring (THC: 5.7±0.3vs vehicle: 12.2±1.8 ng/ml). However, there were no significant differences in basal plasma LH levels or in testicular weights of the male offspring. Thymus weight and total number of thymocytes were significantly higher in THC-exposed male and female rats when compared to vehicle controls. Together, these results indicate that maternal THC exposure has long-lasting effects on reproductive, endocrine and immune parameters of both male and female rat offspring.

Behavioural consequences of maternal exposure to natural cannabinoids in rats

Cannabis sativa preparations (hashish, marijuana) are the most widely used illicit drugs during pregnancy in Western countries. The possible long-term consequences for the child of in utero exposure to cannabis derivatives are still poorly understood. Animal models of perinatal cannabinoid exposure provide a useful tool for examining the developmental effects of cannabinoids. Behavioral consequences of maternal exposure to either cannabis preparations or to its main psychoactive component, delta 9-tetrahydrocannabinol (THC) in rat models are reviewed in this paper. Maternal exposure to cannabinoids resulted in alteration in the pattern of ontogeny of spontaneous locomotor and exploratory behavior in the offspring. Adult animals exposed during gestational and lactational periods exhibited persistent alterations in the behavioral response to novelty, social interactions, sexual orientation and sexual behavior. They also showed a lack of habituation and reactivity to different illumination conditions. Adult offspring of both sexes also displayed a characteristic increase in spontaneous and water-induced grooming behavior. Some of the effects were dependent on the sex of the animals being studied, and the dose of cannabinoid administered to the mother during gestational and lactational periods. Maternal exposure to low doses of THC sensitized the adult offspring of both sexes to the reinforcing effects of morphine, as measured in a conditioned place preference paradigm. The existence of sexual dimorphisms on the developmental effects of cannabinoids, the role of sex steroids, glucocorticoids, and pituitary hormones, the possible participation of cortical projecting monoaminergic systems, and the mediation of the recently described cannabinoid receptors are also analyzed. The information obtained in animal studies is compared to the few data available on the long-term behavioral and cognitive effects on in utero exposure to cannabis in humans.

Prenatal dexamethasone or stress but not ACTH or corticosterone alter sexual behavior in male rats

Prenatal maternal stress in rats and mice can demasculinize and feminize the sexual behavior of adult male offspring. Causal mechanisms are unknown, but one attractive hypothesis is that stress activation of maternal adrenal glucocorticoid secretion is the responsible agent. To test this hypothesis, pregnant rats were exposed to a variety of substances which enhance glucocorticoid actions. These included ACTH (20 IU of a gel preparation, SC once daily), corticosterone (CORT; 7 mg/kg SC in oil, three times daily), or dexamethasone (DEX; 0.1 mg/kg, SC once daily). Controls included noninjected dams and a positive stress control group (restraint under bright lights three times daily). All treatments reduced maternal weight gain, DEX most potently. No treatment altered litter size, stillbirths, or sex ratio, but DEX reduced weight at birth, an effect still seen at postnatal day 85. DEX, CORT, and stress reduced male adrenal weight at birth, while DEX and CORT altered sexual differentiation as measured by anogenital distance. Stress impaired adult male sexual performance but not the lordosis quotient following exposure of animals to stud males. DEX affected both measures. No other treatment had any significant effect on sexual behavior. No treatment altered plasma LH levels, either basal or in response to an estrogen challenge in adult gonadectomized males. In adulthood there was no treatment effect on stress reactivity, measured behaviorally or by plasma glucocorticoids. Correlational analysis revealed that weight gain during pregnancy was the single best predictor of subsequent sexual performance. It is concluded that prenatal dexamethasone exposure demasculinizes and feminizes male offspring.(ABSTRACT TRUNCATED AT 250 WORDS)

Perinatal exposure to delta 9-tetrahydrocannabinol (delta 9-THC) leads to changes in opioid-related behavioral patterns in rats

Perinatal exposure to cannabinoids has been shown to elicit central nervous system impairment in rodents. This includes changes in monoaminergic and neuropeptidergic activities. We have examined the effect of perinatal exposure to delta 9-tetrahydrocannabinol (delta 9-THC) on sensitivity to radiant heat in both male and female rats on days 24, 50 and 70 after birth. Animals used in this experiment were born of mothers that received delta 9-THC (5 mg/kg; p.o.) daily from day 5 of pregnancy until day 24 after offspring birth. delta 9-THC perinatally treated males, but not females, showed higher baseline tail-flick values than controls on days 24 and 50 (Day 24, controls: 3.88 +/- 0.18 s; delta 9-THC group: 4.51 +/- 0.18 s; Day 50, controls: 3.16 +/- 0.17 s; delta 9-THC group: 4.38 +/- 0.38 s). In addition, adult males were found to be tolerant to the analgesic effect of morphine (5 mg/kg; i.p.; % analgesia: controls 71.75 +/- 10.20; delta 9-THC 35.5 +/- 10.59). Moreover, recently weaned pups that received 5 mg/kg of naloxone (i.p.) developed an opioid-like withdrawal syndrome. Taken together all these results suggest that perinatal treatment with delta 9-THC may alter the functionality of the endogenous opioid system, including changes in pain sensitivity.

Perinatal exposure to cannabinoids alters neurochemical development in rat brain

Adult female rats received daily oral doses of delta 9-tetrahydrocannabinol (delta 9-THC), delta 8-THC and cannabidiol (CBD) throughout gestation and lactation. The offspring were sacrificed at various ages and tissue samples of cerebral cortex and striatum were assayed for alpha 1-adrenergic and D2-dopaminergic receptors, respectively. In addition, tyrosine hydroxylase activity was determined in the striatum. The Kd for ligand binding to alpha 1 receptors in the cerebral cortex was significantly increased in 10-day-old offspring exposed to CBD. Significant increases in the Bmax of these receptors occurred at 20 days of age following perinatal exposure to delta 9-THC or delta 8-THC. Exposure to CBD increased the Kd of D2 receptors in the striatum of 10 and 20-day-old offspring compared to control. There were no significant treatment effects on the Bmax of D2 receptors in the striatum at any age. Tyrosine hydroxylase activity was significantly decreased only at 60 days of age in offspring exposed to delta 8-THC or CBD. These results differ from those previously reported with a crude marihuana extract, suggesting that changes in the development of brain catecholamine mechanisms resulting from perinatal exposure to marihuana extracts may be due to an additional constituent of the extract, interactions between specific cannabinoids or other unknown factors.

Maternal cannabinoid exposure. Effects on spermatogenesis in male offspring

Maternal exposure to cannabinoids influenced spermatogenesis and fertility in their male offspring examined at 60-80 days of age. Approximately 20% less spermatozoa were found in males whose mothers had received either the non-psychoactive cannabinol (CBN) or cannabidiol (CBD) on day 1 postpartum. Males exposed to the major psychoactive component of marihuana, delta 9-tetrahydrocannabinol (THC) appeared to have spermatozoa in number comparable to controls. This finding may be consistent with the additional observation that CBN or CBD, but not THC, reduced the percentage of successful impregnations by cannabinoid-exposed males. However, males exposed to each of these cannabinoids produced significantly less live offspring compared to controls. Plasma levels of testosterone and luteinizing hormone (LH) were reduced significantly in mice exposed to THC on day 12 of gestation, while testicular weight was reduced in adult mice exposed either on day 12 of gestation to CBD or on day 1 post-partum to THC. These results indicate that perinatal exposure to psychoactive and non-psychoactive components of marihuana can produce long-term disruption of testicular function including the spermatogenic as well as the steroidogenic components.

Perinatal cannabinoid exposure: effects on hepatic cytochrome P-450 and plasma protein levels in male mice

Maternal exposure to the major psychoactive delta 9-tetrahydrocannabinol (THC), or to the nonpsychoactive cannabinol (CBN) or cannabidiol (CBD) on day 12 of gestation, or on day 1 postpartum, affected the concentrations of hepatic cytochromes P-450 in adult male offspring. Levels of P-450 were significantly increased in adult males prenatally exposed to cannabinoids, but were reduced after postnatal exposure. The response to exogenous testosterone was also differentially affected by perinatal cannabinoid exposure, with reduced plasma androgen in males prenatally exposed to THC, but increased levels of hormone in mice exposed postnatally to THC or CBN. There was a concomitant decrease in plasma albumin and increased gamma-globulin in adult males postnatally exposed to CBN. Beta-globulin levels were also significantly increased in adult males exposed to cannabichromene (CBC) on day 1 postpartum. Cannabinoid exposure during perinatal periods of development exert effects on hepatic function, plasma androgen levels, and on the immune system. These effects may reflect the ability of perinatal cannabinoid exposure to interfere with androgen-mediated processes of differentiation.

The effect of delta 9-tetrahydrocannabinol in utero exposure on rat offspring fertility and ventral prostate gland morphology

Male rats exposed in utero to delta 9-tetrahydrocannabinol (delta 9-THC) had lower levels of testosterone (T) and luteinizing hormone (LH) prior to puberty (P less than 0.01). At puberty, the levels returned to within the normal range. Ultrastructural examination of the ventral prostate gland at puberty revealed alterations suggestive of degenerative changes. A drastic reduction in secretory granules and acini reflected depressed androgen production and function during the developmental period. The fertility of the F1 and F2 male offspring was decreased by 30 to 40%. It is concluded that THC exposure in utero caused a permanent reduction in fertility and altered ventral prostate gland morphology.

Effects of psychoactive and non-psychoactive cannabinoids on neuroendocrine and testicular responsiveness in mice

Repeated oral administration of the non-psychoactive cannabinol (CBN; 5 or 50 mg/kg) significantly reduced the concentration of norepinephrine (NE) in median eminence and greatly reduced NE levels 1 and 2 hrs after administration of alpha-methylparatyrosine (alpha-MPT). The levels of dopamine (DA) in median eminence were significantly different, as indicated by the differences in slopes obtained in CBN- treated and control mice before and after alpha-MPT. Plasma levels of luteinizing hormone (LH) were significantly reduced in CBN-exposed mice before alpha-MPT, elevated at 1 hr post-injection, but were also reduced 2 hrs post-injection at 50 mg/kg CBN. Follicle-stimulating hormone (FSH) levels were increased at 1 hr post-alpha-MPT in mice receiving 50 mg/kg CBN. Oral administration of CBN at 50 mg/kg for 4 days enhanced testicular testosterone (T) production in response to intratesticular in vivo injection of 2.5 or 25 mIU human chorionic gonadotropin (hCG). A single oral dose of the psychoactive delta 9-tetrahydrocannabinol (THC) enhanced the production of T 15 min after intratesticular LH (10 ng) injection. However, at 45 or 60 min post-THC treatment, the response to LH was significantly attenuated. These studies demonstrate that both psychoactive and non-psychoactive components of marihuana alter testicular responsiveness to gonadotropins in vivo. These effects may be biphasic, involving stimulation and inhibition of responsiveness, and appear to be correlated with alterations in plasma LH levels. Alterations in plasma gonadotropins may be mediated by cannabinoid effects on catecholamine concentrations in median eminence and THC-induced alterations in testicular responsiveness to gonadotropin probably also involve direct effects of THC at the gonadal level.

Suppression of male copulatory behavior by delta 9-THC is not dependent on changes in plasma testosterone or hypothalamic dopamine or serotonin content

Castrated B6D2 F1 male mice were tested for their sexual responses after being administered 0.5 mg/kg delta 9-tetrahydrocannabinol (THC) 50 mg/kg THC or oil. The animals that received 50 mg/kg, but not 0.5 mg/kg THC, showed deficits in copulatory behavior. Another group of B6D2 F1 castrates were given testosterone propionate (TP) replacement therapy plus 50 mg/kg THC or oil. Similarly, those mice which received 50 mg/kg THC showed behavioral deficits. Lastly, a group of intact B6D2 F1 males were treated with 0.5 mg/kg THC, 50 mg/kg THC or oil, were bled and decapitated, and their brains removed 10 min or 4 hr after treatment. Plasma testosterone (T) and hypothalamic dopamine (DA) levels were unaltered 4 hr after treatment with 50 mg/kg THC, but the concentration of serotonin (5-HT) in their hypothalami was elevated. This effect of THC on hypothalamic 5-HT concentration was not apparent in a larger group of randomly bred animals that were tested. These data strongly suggest that THC's behavioral effects are not mediated by variations in T levels, or by changes in hypothalamic 5-HT or DA concentrations.

Marihuana: much ado about THC

The availability of delta 1-THC, the major psychoactive component of marihuana, in pure form offered an opportunity for better understanding of the mechanism of action of this drug. Two decades after the isolation of delta 1-THC its mode of action is still obscure despite the enormous amount of research invested in it. Studying cannabis content as a whole offers a different approach for better understanding of this ancient weed and its effects.