Reproductive and teratologic studies with delta9-tetrahydrocannabinol and crude marijuana extract

The endogenous cannabinoid system modulates male sexual behavior expression

The endocannabinoid system (ECS) plays a key neuromodulatory role in the brain. Main features of endocannabinoids (eCBs) are that they are produced on demand, in response to enhanced neuronal activity, act as retrograde messengers, and participate in the induction of brain plasticity processes. Sexual activity is a motivated behavior and therefore, the mesolimbic dopaminergic system (MSL) plays a central role in the control of its appetitive component (drive to engage in copulation). In turn, copulation activates mesolimbic dopamine neurons and repeated copulation produces the continuous activation of the MSL system. Sustained sexual activity leads to the achievement of sexual satiety, which main outcome is the transient transformation of sexually active male rats into sexually inhibited animals. Thus, 24 h after copulation to satiety, the sexually satiated males exhibit a decreased sexual motivation and do not respond to the presence of a sexually receptive female with sexual activity. Interestingly, blockade of cannabinoid receptor 1 (CB1R) during the copulation to satiety process, interferes with both the appearance of the long-lasting sexual inhibition and the decrease in sexual motivation in the sexually satiated males. This effect is reproduced when blocking CB1R at the ventral tegmental area evidencing the involvement of MSL eCBs in the induction of this sexual inhibitory state. Here we review the available evidence regarding the effects of cannabinoids, including exogenously administered eCBs, on male rodent sexual behavior of both sexually competent animals and rat sub populations spontaneously showing copulatory deficits, considered useful to model some human male sexual dysfunctions. We also include the effects of cannabis preparations on human male sexual activity. Finally, we review the role played by the ECS in the control of male sexual behavior expression with the aid of the sexual satiety phenomenon. Sexual satiety appears as a suitable model for the study of the relationship between eCB signaling, MSL synaptic plasticity and the modulation of male sexual motivation under physiological conditions that might be useful for the understanding of MSL functioning, eCB-mediated plasticity and their relationship with motivational processes.

Influence of prenatal cannabinoid exposure on early development and beyond

Public perception surrounding whether cannabis use is harmful during pregnancy often diverges greatly from the recommendations of doctors and healthcare providers. In contrast to the medical guidance of abstinence before, during, and after pregnancy, many women of reproductive age believe cannabis use during pregnancy is associated with little potential harm. Legalization and social cues support public perceptions that cannabis use during pregnancy is safe. Moreover, pregnant women may consider cannabis to be a safe alternative for treating pregnancy related ailments, including morning sickness. Compounding the problem is a lack of medical and federal guidance on safe, low, or high-risk levels of cannabis use. These issues mirror the continuing debate surrounding alcohol use and health, in particular, whether there are safe or lower risk levels of alcohol consumption during pregnancy. Clinical studies to date suffer from several limitations. First, most human studies are correlative in nature, meaning that causal associations cannot be made between in utero cannabis exposure and health and behavioral outcomes later in life. Due to obvious ethical constraints, it is not possible to randomly assign pregnant mothers to cannabis or other drug exposure conditions-a requirement needed to establish causality. In addition, clinical studies often lack quantitative information on maternal exposure (i.e., dose, frequency, and duration), include a small number of individuals, lack replication of outcome measures across cohorts, rely on self-report to establish maternal drug use, and suffer from unmeasured or residual confounding factors. Causal associations between maternal cannabis exposure and offspring outcomes are possible in preclinical cohorts but there is a large amount of heterogeneity across study designs and developmental differences between rodents and humans may limit translatability. In this review, we summarize research from human and preclinical models to provide insight into potential risks associated with prenatal cannabinoid exposure (PCE). Finally, we highlight gaps in knowledge likely to contribute to the growing divide between medical guidance and public attitudes regarding cannabis use during pregnancy.

Developmental Effects of Cannabidiol and Δ9-Tetrahydrocannabinol in Zebrafish

Cannabidiol (CBD) has gained much attention in the past several years for its therapeutic potential in the treatment of drug-resistant epilepsy, such as Dravet syndrome. Although CBD has shown anecdotal efficacy in reducing seizure frequency, little is known regarding the potential adverse side effects of CBD on physiology, development, organogenesis, or behavior. The goal of this project was to compare the relative morphological, behavioral, and gene expression phenotypes resulting after a developmental exposure to Δ9-tetrahydrocannabinol (THC) or CBD. Zebrafish were exposed from blastula through larval stage (96 h postfertilization [hpf]) to 0.3, 0.6, 1.25, 2.5, 5 mg/l (1, 2, 4, 8, 16 µM) THC or 0.07, 0.1, 0.3, 0.6, 1.25 mg/l CBD (0.25, 0.5, 1, 2, 4 µM). Despite the similarity in THC and CBD dysmorphologies, ie, edemas, curved axis, eye/snout/jaw/trunk/fin deformities, swim bladder distention, and behavioral abnormalities, the LC50 for CBD (0.53 mg/l) was nearly 7 times lower than THC (3.65 mg/l). At 96 hpf, c-fos, dazl, and vasa were differentially expressed following THC exposure, but only c-fos expression was significantly increased by CBD. Cannabidiol was more bioconcentrated compared with THC despite higher THC water concentrations. This work supports the potential for persistent developmental impacts of cannabinoid exposure, but more studies are needed to assess latent effects and their molecular mechanisms of toxicity.

A cannabinoid analogue of Delta9-tetrahydrocannabinol disrupts neural development in chick

Marijuana is the most commonly abused illicit drug by pregnant women. Its major psychoactive constituent, Delta(9)-THC (Delta(9)-tetrahydrocannabinol), crosses the placenta and accumulates in the foetus, potentially harming its development. In humans, marijuana use in early pregnancy is associated with miscarriage, a fetal alcohol-like syndrome, as well as learning disabilities, memory impairment, and ADHD in the offspring. Classical studies in the 1970 s have reached disparate conclusions as to the teratogenic effects of cannabinoids in animal models. Further, there is very little known about the immediate effects of Delta(9)-THC on early embryogenesis. We have used the chick embryo as a model in order to characterize the effects of a water-soluble Delta(9)-THC analogue, O-2545, on early development. Embryos were exposed to the drug (0.035 to 0.35 mg/ml) at gastrulation and assessed for morphological defects at stages equivalent to 9-14 somites. We report that O-2545 impairs the formation of brain, heart, somite, and spinal cord primordia. Shorter incubation times following exposure to the drug show that O-2545 interferes with the initial steps of head process and neural plate formation. Our results indicate that the administration of the cannabinoid O-2545 during early embryogenesis results in embryotoxic effects and serves to illuminate the risks of marijuana exposure during the second week of pregnancy, a time point at which most women are unaware of their pregnancies.

Marihuana and tobacco use in pregnancy

Marihuana and tobacco smoking are two of the most commonly abused substances in pregnancy. Smoke from both agents contain a multitude of potentially active components, which make them difficult to study. Both have been associated with adverse effects in pregnancy in animal and human studies. Data on marihuana use during pregnancy have been conflicting. There is much evidence, however, demonstrating adverse pregnancy outcomes associated with cigarette smoking which, fortunately, can be reversed with smoking cessation.

Effects of delta 9-tetrahydrocannabinol, phenobarbital, and their combination on pregnancy and offspring in rats

delta 9-THC, sodium phenobarbital, or a combination of these drugs, were administered to pregnant mice on gestation days 6 to parturition. Levels of delta 9-THC in blood approximated levels attained in humans after smoking one to two marijuana cigarettes. Blood cannabinoid levels in mice were not significantly elevated by concurrent drug administration. Both drugs significantly reduced litter size and weight per pup at birth, but the combination of these drugs did not affect these outcomes to a significantly greater degree than either drug by itself. Phenobarbital but not delta 9-THC increased resorption rate.

Effects of delta-9-tetrahydrocannabinol, chlordiazepoxide (Librium), and their combination on pregnancy and offspring in mice [correction of rats]

Delta-9-tetrahydrocannabinol (THC), chlordiazepoxide hydrochloride (Librium) or a combination of these drugs, were administered to pregnant mice on gestation days 6 to parturition. Levels of THC in blood were dose-related and approximated levels attained in humans after smoking one to two marijuana cigarettes. Blood cannabinoid levels in mice were elevated by concurrent administration of chlordiazepoxide. Maternal weight gain was significantly reduced by THC but not by chlordiazepoxide. Neither drug affected implantations, but THC significantly increased resorptions. Both THC and chlordiazepoxide decreased fetal weight. There was no indication of synergism between the two drugs for any of the measures examined in this study.

Alcohol enhancement of marihuana-induced fetotoxicity

In two separate studies marihuana and alcohol were administered, either separately or in combination, to pregnant mice or rats. Control animals were given vehicle only or were nontreated. Marihuana-, alcohol-, and vehicle-treated animals were pair-fed and pair watered with animals given marihuana plus alcohol, to control for drug-related undernutrition. The combination of marihuana and alcohol caused a 100% fetomortality in mice and a 73% fetomortality in rats, whereas neither marihuana nor alcohol alone had any effects on fetomortality that differed significantly from vehicle treatment. These studies suggest a potential danger to pregnancy resulting from the combined use of two commonly used drugs that is far greater than that associated with use of either drug alone.

Regulation of visual attention in offspring of female monkeys treated chronically with delta 9-tetrahydrocannabinol

Visual attention was studied in a group of rhesus monkey infants whose mothers received daily oral treatment with low levels of delta 9-tetrahydrocannabinol (THC, 2,4 mg/kg/day) prior to and during pregnancy and throughout lactation (3.5 postnatal months). Attention was measured at 1 and 2 years of age in a standardized test situation in which animals looked at projected slides. In comparison with controls (offspring of untreated mothers), THC offspring directed more attention at slides on the 1st trial of a session. The THC offspring also engaged in relatively longer individual periods of attention on the 1st vs 2nd trials of the session and during the 1st vs 2nd session in which a given slide was presented. Further experiments varying novelty and complexity of visual stimuli suggested that changes in visual attention of THC offspring can be characterized as a failure to limit the response to novel stimuli.

Interactive effects of nutrition and cannabis upon rat perinatal development

In order to examine the effects of cannabinoids, malnutrition, and their possible interaction upon the developing rat fetus, female Wistar rats were exposed to cannabis smoke, placebo smoke, or no smoke while concurrently consuming 1 of 3 diets differing in protein concentration (8%, 24%, 64%). Both the diet and drug treatments were administered 20 days prior to and throughout gestation. Of the 12 variables affected by the low-protein diet, 8 were significantly potentiated when undernutrition was combined with cannabis treatment. Some dependent variables that were not altered either by the low-protein diet or by cannabis inhalation were affected by the combination of treatments. These included a lengthened gestation period, an increase in occurrence of stillbirths and litter destruction, and decreased activity in the rat pups. Cannabis coupled with a standard protein diet resulted in a number of developmental indices being delayed but combining the drug with an enriched protein diet ameliorated these effects. The evidence also suggests that the administration of cannabis both before and during gestation resulted in a degree of tolerance to some aspects of the drug effects.

Behavioral effects of hashish in mice. II. Nursing behavior and development of the sucklings

Adult mice were treated from parturition to weaning of their first litter with a hashish extract containing 40% delta 9-tetrahydrocannabinol (delta 9-THC), 45% cannabidiol, 9% cannabinol, and 6% other cannabinoids. Oral administrations of 20 mg delta 9-THC/kg three times a week decreased the weight gain of pups from days 3-6 and 6-10 significantly, resulting in about 15% lower body weights on days 6 and 10 compared with control sucklings. Other parameters of development such as the general appearance of the pups were little affected, except for a slight tendency by day 13, when some additional control pups already had both eyes open. The effects of hashish in sucklings might be caused by drug intake with mother's milk, as well as by a decreased lactation of drugged dams. In addition, our pup retrieving tests at the day 3, 1.5-2 h after the second application of hashish extract, showed a decrease in the mother's locomotive and nonsocial activities and pointed to at least transient impairment of the maternal behavior. By day 10, after the fifth administration of hashish extract, a partial tolerance occurred, with normal care for the young, but still decreased nonsocial activities of the drugged dams. Thus our experiments showed distinct effects of cannabis on mice litters when the parents were drugged postnatally during the period of lactation only.

Effects of marihuana on pregnant rats and their offspring

Pregnant rats were intubated with marihuana extract (10, 150 mg/kg) from gestation day 3 to parturition. Control animals were pair-fed. At parturition pups were culled and assigned to nondrug-treated dams. A positive control group consisting of animals prenatally exposed to alcohol (6 g/kg/day) was included for comparison of birth weight data. Marihuana reduced food and water consumption and maternal weight gain. Pup weight at birth was reduced by about 10% relative to pair-fed controls in animals exposed to the high doses of marihuana, and by approximately 15% in pups exposed to alcohol relative to their pair-fed controls. Litter size and pup mortality at birth were not affected significantly. Postnatal mortality was increased and neonatal weight was decreased at 21 days in marihuana-treated offspring. At 11 weeks of age body weights of drug-treated females but not males, were still significantly less than that of pair-fed controls.

Teratologic evaluation of synthetic delta 9-tetrahydrocannabinol in rabbits

Synthetic delta 9-tetrahydrocannabinol (THC) was dissolved in undiluted propylene glycol and administered in daily subcutaneous doses of 15.0, 30.0 or 60.0 mg/kg to pregnant New Zealand white rabbits on days 7--19 of gestation. Maternal food consumption and weight gain were markedly reduced at all dose levels. Embryotoxicity and embryocidal effects were observed in the form of reduced litter weight and number of viable fetuses, respectively, in offspring from pregnant mothers treated with THC. However, on the basis of extensive external, visceral and skeletal examination of all fetuses it may be concluded that THC is not teratogenic in the New Zealand white strain rabbit following subcutaneous administration of doses as high as 60.0 mg/kg/day during the critical period of organogenesis (days 7--19 of gestation). On the other hand, an oral dose of thalidomide (200.0 mg/kg/day), the positive control used in this study, was both embryocidal and teratogenic.