Convulsant-anticonvulsant properties of delta-9-tetrahydrocannabinol in rabbits

Sound stimulation causes audiogenic seizures (AGS) in ACEP/J, but not Uaz:NZW-thc, rabbits. Delta-9-tetrahydrocannabinol (THC) causes behavioral seizures in the latter, but not in the former, rabbits. Also, delta-9-THC blocks AGS in ACEP/J rabbits. These results support the concept that the genes conferring seizure susceptibility to these two rabbit populations are different.     

Muricide induced by single injection of delta9-tetrahydrocannabinol

Male rats were subjected to 22 hr of food deprivation and 24 hr of isolated housing and then Δ⁹-tetrahydrocannabinol (THC) was intraperitoneally injected. One hour after treatment, the dose-related muricide was observed. Next, the relationship between the duration of isolated housing and muricide was investigated. Regardless of the time at which THC was injected during periods of isolation ranging from 2 hr to 30 days, or even the animals were isolated concurrently to THC injection, muricide appeared at an incidence of 60–80%, and was unrelated to the duration of isolated housing. Muricide was not induced in communally housed rats treated with THC, but by placing these animals in isolation 1 hr after treatment, the time of peak effect of THC, muricide occurred in 70% of the rats. These results demonstrate that if the rat is placed in isolation within the period of the effect of THC, muricide is induced.     

The urinary calcium/creatinine ratio as a measure of urinary calcium excretion

Urine specimens were collected from 26 normal subjects, 10 patients with proven primary hyperparathyroidism, and eight patients with hypercalcaemia due to other causes. After overnight urine concentration, an oral water load was given to induce a diuresis and provide urine specimens with a relatively wide range of creatinine concentration for each subject. In normal subjects the urinary calcium/creatinine ratio was found to be independent of urine concentration. In eight out of 10 patients with primary hyperparathyroidism and in two out of eight patients with hyper-calcaemia due to other causes, the urinary calcium/creatinine ratio was found to be high when the creatinine concentration was low, but usually normal when the creatinine concentration was high. The results suggest that if the urinary calcium/creatinine ratio of random urine specimens is used as a ;screening' procedure to detect hypercalciuria the latter cannot be excluded if the urinary creatinine concentration is more than 40 mg per 100 ml.     

No sex difference in the urinary excretion of the histamine metabolite methylimidazoleacetic acid (MeImAA) when corrected for creatinine excretion

Inflammation Research -     

The ontogeny of delta-9-tetrahydrocannabinol responsiveness in the rabbit

An autosomal recessive condition (thc/thc) in our closed colony of New Zealand White rabbits (Uaz:NZW-thc) results in nonfatal, behavioral convulsions following intravenous (i.v.) injections of delta-9-tetrahydrocannabinol (THC) and other psychoactive cannabinoids of marijuana. The ontogeny of the convulsive response was evaluated in potential THC-seizure-susceptible (SS) rabbits from postnatal Days (PN) 15-548. Ages of nonsusceptibility (PN 15-23), partial susceptibility (PN 24-38), and complete susceptibility (PN 39-548) were found. Also, open-field activity was determined in PN 14-25 THC-SS and THC-seizure-resistant (SR) rabbits. Administration of THC during the seizure-insensitive period resulted in genotype-dependent alternations in photocell activity and sprawling.     

Delta-9-tetrahydrocannabinol inhibits the splenocyte proliferative response to herpes simplex virus type 2

The present investigation was undertaken to determine the effect of in vivo Delta-9-tetrahydrocannabinol (Delta-9-THC) treatment on immune responsiveness to secondary exposure to herpes simplex virus type 2 (HSV2) antigens in vitro. A splenocyte proliferative assay, employing HSV2-infected mouse embryo fibroblasts as target cells, was used to measure immune responsiveness. Administration of 50 mg/kg or 100 mg/kg Delta-9-THC to B6C3F1 mice in concert with HSV2 infection resulted in suppression of the proliferative response to HSV2 cell-surface antigens expressed on virus-infected mouse embryo fibroblasts. Similarly, in vitro treatment of HSV2-infected cells with Delta-9-THC (10(-7) M to 10(-5) M) resulted in a dose-dependent suppression of proliferative responsiveness of splenocytes of non-drug-treated HSV2-sensitized mice. These results suggest that Delta-9-THC inhibits immune responsiveness of B6C3F1 mice to homotypic challenge with HSV2. This inhibition may be resultant of drug action on both effector immunocytes and target HSV2 antigen-bearing cells.     

Relationship of aging and cytokines to the immunomodulation by delta-9-tetrahydrocannabinol on murine lymphoid cells

The effect of delta 9-tetrahydrocannabinol, the major psychoactive component of marijuana, was investigated utilizing lymphoid cells from 2-week, 2-month, and 18-month-old mice. Previous studies have shown a differential modulation by THC related to age such that cells from adult mice could be up-regulated by THC when stimulated by their CD3 receptor. Cells from 2-week-old and 18-month-old mice were resistant to this THC-mediated enhancement. This paper questioned whether these resistant cells could be up-regulated by either addition or removal of cytokines or by exposure to supernatants derived from adult cells. IL-1, IL-4, and IL-6 modified cell proliferation in general, and their effects had some age-related differences, but these actions were independent of THC. In contrast, the THC-induced enhancement appeared to be related in part to IL-2 levels in the adult cell cultures such that when IL-2 was removed, not only did up-regulation not occur, but THC was, in fact, suppressive. Addition of IL-2 or supernatants from adult cells did lead to a modified THC-induced up-regulation of proliferation in cells from adult or 2-week-old mice. Cells from 18-month-old mice remained resistant to this modulation by THC. This did not represent a general anergy of these older cells since they did proliferate well in culture. These results demonstrate a difference in immune response to THC related to the age of the mice which correlates at least in part to IL-2 levels in 2-week-old and young adult mice. THC modulation, whether immunoenhancing or suppressing, appears to be influenced by the presence of other cell stimulators such as cytokines, and is sensitive to the timing of THC exposure relative to such stimuli.     

Enhanced susceptibility of mice to combinations of delta 9-tetrahydrocannabinol and live or killed gram-negative bacteria.

Combinations of delta 9-tetrahydrocannabinol (delta 9-THC) and bacterial endotoxin were shown to be hyperadditively toxic for mice. A variety of purified lipopolysaccharide (LPS) preparations elicted enhanced mortality in combination with delta 9-THC. Escherichia coli O26:B6 LPS (Boivin preparation) at an essentially nonlethal dose of 2.5 mg/kg reduced the dose of delta 9-THC required to kill 50% of the treated mice from ca. 350 to 150 mg/kg. Inbred BALB, DBA, and C3H/HeCr mice, noninbred ICR mice, and hybrid CDF1 and BDF1 mice were hyperreactive to combinations of delta 9-THC and LPS. Moreover, a variety of heat-killed intestinal and gram-negative bacteria, live E. coli, and complexes of lipid A with a variety of proteins substituted for LPS in the synergistic toxicity of LPS and delta 9-THC. Extracts of marijuana also elicited hyperreactivity to LPS. The hyperadditive lethality of combinations of delta 9-THC and LPS was markedly less in mice rendered refractory to LPS or delta 9-THC by repeated administration of LPS or delta 9-THC, respectively.     

Differential suppression of T-cell subpopulations by thc (delta-9-tetrahydrocannabinol)

THC (delta-9-tetrahydrocannabinol), the major psychoactive component of marijuana, has been shown to suppress various immune functions in vivo and in vitro. THC suppresses murine T-lymphocyte proliferation; however, the effects on T-cell subsets remain unclear. We have stimulated cultured murine splenocytes with the mitogens concanavalin A (Con A) or phytohemagglutinin (PHA) while exposing them to varying concentrations of THC. After three days, the cells were analyzed by the fluorescent activated cell sorter for the following T-cell markers--Thy1, L3T4 and Ly2. The Ly2 cells represent the suppressor/effector T-cells while L3T4 cells represent the helper T-cell subpopulations. The results show that the dose response suppressive effect of THC on T-cell proliferation reflects a preferential inhibition of Ly2 vs L3T4 cells. The effects of THC on other functional parameters are in the process of investigation.     

Effects of delta-9-tetrahydrocannabinol on cultured HeLa cell growth and development

Monolayer cultures of HeLa cells were used to monitor the effects of non-lethal concentrations of delta-9-tetrahydrocannabinol (delta-9-THC) on the pool sizes of the acid-soluble and acid-insoluble DNA moieties and cytoplasmic RNA pool sizes. The DNA fractions were separated using acid precipitation and low speed centrifugation, while the RNA was examined through the use of sucrose gradients and high speed ultracentrifugation. The ratio of acid-insoluble to acid-soluble DNA per cell in untreated HeLa cells is 16:1, which did not change appreciably following delta-9-THC treatment. However, cell division was retarded as much as 25% in the 24 hours treatment period indicating that nucleic acid synthesis, while not inhibited, is depressed by delta-9-THC. This is not related to cell death as indicated by cell viability (> 95%). At both 1.0 x 10(-5)M and 3.2 x 10(-7)M, delta-9-THC caused a marked change in the free ribosomal RNA (an increase with 3.2 x 10(-7)M and a decrease with the 10(-5)M), total ribosomal RNA (a decrease with both observed delta-9-THC concentrations) and non-sedimental RNA (an increase with both observed delta-9-THC concentrations).     

Suppression of human macrophage function in vitro by delta 9-tetrahydrocannabinol.

The ability of macrophages to function in the presence of delta 9-tetrahydrocannabinol (THC), the major psychoactive component in marijuana, was evaluated. THC added to macrophage cultures prepared from human peripheral blood inhibited macrophage spreading and phagocytosis of yeast. The effects of THC were concentration dependent, with inhibitory effects observed from 10 to 1 micrograms/ml or lower. These results suggest that macrophages are more sensitive to THC than are lymphocytes because macrophage functions were inhibited by THC at concentrations that did not affect lymphocyte function. Thus, inhibition of lymphocyte function(s) by THC could be attributed to a direct effect of the drug on macrophages which indirectly results in lowered lymphoid cell activity.     

Mifepristone or inhibition of 11beta-hydroxylase activity potentiates the sedating effects of the cannabinoid receptor-1 agonist Delta(9)-tetrahydrocannabinol in mice

The cannabinoid system is a regulator of neurotransmission and is linked with hormonal control. We have found in experimental mouse studies that the progesterone receptor inhibitor mifepristone (RU38486, 80 mg/kg i.p.) or the 11beta-hydroxylase inhibitor metyrapone (100 mg/kg i.p.) when administered in combination with cannabinoids potentiates the transient-sedating cannabinoid receptor-1 effects of a high-dose Delta(9)-tetrahydrocannabinol (25 mg/kg i.p.), causing severe prolonged sedation associated with hypomotility, catalepsy and hypothermia. This observation has implications for human subjects taking these drugs and related compounds particularly because of the ubiquitous use of cannabis and the high potential for mifepristone and related compounds to become available on the 'black-market' as abortifacients.     

Interactive effects of chronic phencyclidine and delta 9-tetrahydrocannabinol on spermatogenesis in mice

In this study, the combined effects of chronic phencyclidine (PCP) and delta 9-tetrahydrocannabinol on spermatogenesis in mice were examined. Mice were treated with THC (50 mg/kg, PO) and PCP (15 mg/kg, IP) alone or in combination for 16 days and with PCP alone for 35 days. THC had a significant effect on spermatogenesis and decreased the number of all germinal cells. PCP, on the other hand, affected all germinal cells except spermatids after 35 days of treatment. Combination of THC and PCP treatment caused a significant decrease in resting and pachytene spermatocytes. Similarly, combination of these two drugs caused a significant increase in cauda epididymal abnormal sperms. These results suggest that THC and PCP may cause greater disruption in spermatogenesis when they are abused together.     

Secondary immunity to Legionella pneumophila and Th1 activity are suppressed by delta-9-tetrahydrocannabinol injection.

Resistance to infection with Legionella pneumophila is primarily dependent upon cell-mediated immunity rather than humoral immunity. Recent evidence suggests that activation of cell-mediated immunity depends on Th1 cells and activation of humoral immunity depends on Th2 cells. In this report, delta 9-tetrahydrocannabinol (THC), the major psychoactive cannabinoid of marijuana and an immunomodulator, suppressed development of secondary immunity to L. pneumophila, which correlated with a reduction in Th1 activity. BALB/c mice, infected with a primary sublethal dose of L. pneumophila, developed resistance to a larger challenge infection 3 to 4 weeks later. However, intravenous injection of THC (4 mg/kg of body weight) 1 day prior to primary infection resulted in increased mortality after the challenge infection. The level of anti-L. pneumophila antibodies in serum increased in both THC-treated and control mice; however, in the THC group IgG1 antibodies which are stimulated by Th2 cells were elevated while Th1-regulated, IgG2a antibodies were depressed. Furthermore, cultured splenocytes from THC-treated mice had less L. pneumophila-specific lymphoproliferation, indicating a deficiency in cell-mediated immunity. Normal mouse splenocytes treated in vitro with THC and pokeweed mitogen showed suppressed production of gamma interferon, a cytokine associated with Th1 cells, but increased production of interleukin 4, a cytokine produced by Th2 cells. Splenocytes from THC-treated mice, stimulated in vitro with either pokeweed mitogen or anti-CD3 antibodies, also produced less gamma interferon, indicating less Th1 activity in these mice. These results suggest that THC decreases the development of anti-L. pneumophila immunity by causing a change in the balance of Th1 and Th2 activities.     

Fluorometric dosage of the delta-9-tetrahydrocannabinol and its metabolites in urine]

The author describes a method of identification and estimation in biological fluids of delta9-THC and its metabolites based on the formation after extraction and suitable binding with Gallium to form highly fluorescent complexes.     

Metastatic tumors to the urinary bladder: clinicopathologic study of 11 cases

Secondary neoplasms of the urinary bladder are uncommon, with metastatic tumors being an even rarer event. The authors studied the clinicopathology of 11 cases of metastatic tumors to bladder, which were collected from their archives between 1995 and 2010. The most common metastases in this series were breast. Some unusual metastases, including several not being previously reported, were also presented, namely, ileal carcinoid tumor, ileal gastrointestinal stromal tumor, ovarian squamous carcinoma, pancreatic gastrinoma, and renal collecting duct carcinoma. Vast majority of these patients (10/11, 91%) were female. Ninety percent of the patients presented with hematuria and/or obstructive urinary symptom as well as bladder lesions in the area of trigone, posterior wall, and/or bladder neck. Seven of the 11 patients had a known history of other metastases besides the bladder. Most of the patients (4/7, 57%) died within 1 year after diagnosis of bladder metastasis. Metastasis must be distinguished from a primary bladder neoplasm. Morphology and clinical correlation supplemented with immunohistochemical study is critical for the correct diagnosis.