Low-dose penicillin in early life induces long-term changes in murine gut microbiota, brain cytokines and behavior.

There is increasing concern about potential long-term effects of antibiotics on children's health. Epidemiological studies have revealed that early-life antibiotic exposure can increase the risk of developing immune and metabolic diseases, and rodent studies have shown that administration of high doses of antibiotics has long-term effects on brain neurochemistry and behaviour. Here we investigate whether low-dose penicillin in late pregnancy and early postnatal life induces long-term effects in the offspring of mice. We find that penicillin has lasting effects in both sexes on gut microbiota, increases cytokine expression in frontal cortex, modifies blood-brain barrier integrity and alters behaviour. The antibiotic-treated mice exhibit impaired anxiety-like and social behaviours, and display aggression. Concurrent supplementation with Lactobacillus rhamnosus JB-1 prevents some of these alterations. These results warrant further studies on the potential role of early-life antibiotic use in the development of neuropsychiatric disorders, and the possible attenuation of these by beneficial bacteria.

Role of cannabinoid receptor agonists in mechanisms of suppression of central pain syndrome.

We studied the effect of cannabinoid receptor agonists anandamide and WIN 55,212-2 on the central pain syndrome induced by intraspinal injection of penicillin sodium salt in rats. Cannabinoids suppressed allodynia and spontaneous attacks in rats with the central pain syndrome. The analgesic effect was most pronounced after intrathecal injection of cannabinoid receptor agonist in a dose of 100 microg in 10 microl. After systemic treatment the analgesic effect was produced by only WIN 55,212-2 in a dose of 1 mg/kg. WIN 55,212-2 was superior to anandamide by the duration and intensity of the effect on allodynia and spontaneous attacks.

Immunoglobulin E-dependent active fatal anaphylaxis in mast cell-deficient mice.

Mast cells have long been believed to be the central effector cells in the development of immunoglobulin (Ig)E-dependent anaphylaxis. In this study, we investigated the role of mast cells in IgE-dependent hapten-induced active fatal anaphylaxis using mast cell-deficient WBB6F1- W/Wv (W/Wv) and congenic normal (+/+) mice. Although a 5-min delay in shock signs and death were observed in W/Wv mice, 100% fatal reactions to penicillin V (Pen V) occurred in both +/+ and W/Wv mice. Administration of monoclonal anti-IL-4 antibody completely prevented the fatal reactions, and the effect of anti-IL-4 was associated with its suppressive activity on Pen V-specific serum levels of IgE, but not IgG. The platelet-activating factor (PAF) antagonist, BN 50739, completely prevented the fatal reactions in both strains of mice. Our kinetic study revealed, in contrast to no elevation of plasma histamine level in W/Wv mice, high levels of PAF in the circulation after challenge in both +/+ and W/Wv mice, albeit to a lesser degree in the latter case. These data indicate that cells other than mast cells are sufficient to induce an IgE-dependent active fatal anaphylaxis by elaborating PAF, which is the critical mediator for fatal murine anaphylaxis.

In vitro and in vivo cytogenetic studies of three beta-lactam antibiotics (penicillin VK, ampicillin and carbenicillin).

The in vitro and in vivo clastogenic potential of three beta-lactam antibiotics, ampicillin, carbenicillin and penicillin VK, was investigated using cultured human lymphocytes and the rat micronucleus test. Neither ampicillin nor carbenicillin induced significant increases in chromosome damage in vitro up to test concentrations of 10 mg/ml. These results contrast with other published studies on these compounds. Both drugs were also inactive in vivo in the rat micronucleus test, using single- or double-dosing regimens (ampicillin 5 g/kg orally; carbenicillin 500 mg/kg i.m., either dosed once 30 h before marrow preparation, or dosed twice 48 and 24 h before marrow preparation). In vitro, penicillin VK induced a dose-related increase in chromosome and chromatid gaps and breaks, down to concentrations of 1.25 mg/ml. It is likely that the increase in aberration frequency was partly the result of exposing the cells to increased K+ ion concentration, as similar results were obtained when potassium chloride was evaluated over the same molar concentration range. However, the occurrence of 'ion-mediated' clastogenic effects as reported by other workers, does not fully account for the positive effects obtained with this compound, as clastogenic effects were also observed with penicillin V in this test system at similar test concentrations. It is known that exposure of mammalian cells to extremely high concentrations of beta-lactams can affect DNA polymerase alpha activity. An inhibitory effect upon DNA polymerase alpha resulting in a breakdown in the structural integrity of the chromosomes, is suggested as an additional mechanism of action for penicillin VK.(ABSTRACT TRUNCATED AT 250 WORDS)

Toxicity studies of amphetamine sulfate, ampicillin trihydrate, codeine, 8-methoxypsoralen, alpha-methyldopa, penicillin VK and propantheline bromide in rats and mice.

Thirteen-week toxicity studies in F344/N rats and B6C3F1 mice were conducted to determine general toxicity and target organ toxicity with amphetamine sulfate, ampicillin trihydrate, codeine, 8-methoxypsoralen, alpha-methyldopa sesquihydrate, penicillin VK, and propantheline bromide. This paper discusses the toxicity observed; use of the toxicity data to set dose levels for subsequent 2-year studies; and comparison of dose levels administered to rodents with doses used in the treatment of human disease. Drugs were administered orally in the feed or by gavage. The lowest doses in the 13-week studies were comparable to therapeutic doses in man on a mg/m2 (body surface area) basis or 5-10 times doses used in man on a mg/kg body weight basis. Little toxicity was seen at the low dose level with ampicillin, penicillin VK, 8-methoxypsoralen or propantheline bromide. At higher doses, target organ toxicity seen included the urinary bladder in male rats after propantheline bromide; the glandular stomach in rats and mice after penicillin VK; the liver and adrenals in rats after 8-methoxypsoralen; and the kidney in mice and rats after alpha-methyldopa. After amphetamine, codeine, or ampicillin administration, no target organ toxicity was seen in rats or mice, even at doses which caused body weight gain depression. The high doses chosen for subsequent 2-year studies were within 10 times human dose levels when compared on a mg/m2 body surface area.

Two-year toxicity and carcinogenicity studies of ampicillin trihydrate and penicillin VK in rodents.

Toxicology and carcinogenesis studies of ampicillin trihydrate and penicillin VK, two widely used beta-lactam antibiotics, were performed in F344/N rats and B6C3F1 mice. In these studies ampicillin trihydrate was administered for 2 years to rats at doses of 0, 750, or 1500 mg/kg and to mice at doses of 0, 1500, or 3000 mg/kg, and penicillin VK was administered to rats and mice at doses of 0, 500, or 1000 mg/kg. Both drugs were administered by oral gavage in corn oil. Toxic lesions of the stomach were seen in rats and mice after ampicillin trihydrate administration and in mice after penicillin VK administration. In male rats that received ampicillin trihydrate there was a marginal increase in incidence of mononuclear cell leukemia and pheochromocytomas of the adrenal gland medulla. There was no evidence for carcinogenic activity in female rats or male and female mice after ampicillin trihydrate administration or in rats and mice after penicillin VK administration.

Cerebral toxicity of penicillins in relation to their hydrophobic character.

The neurotoxic effects of ticarcillin, methicillin, phenthicillin, oxacillin, cloxacillin and dicloxacillin were studied in the conscious rabbit. During and after intravenous administration of 1.2 and 2.4 g/kg, resp., over 50 min the blood concentrations of the drugs were determined and the neurotoxicity assessed by continuous recording of the electroencephalogram. The hydrophobia of the penicillins was characterized by determination of their partition coefficients between isobutanol and buffer solution pH 7.4. The penicillins showed quite different neurotoxic properties. A close correlation (r = 0.928) was found between the neurotoxic potency of the penicillins and their partition coefficients. With increasing hydrophobia the neurotoxic potency increased in the following sequence: Ticarcillin, methicillin, oxacillin, phenethicillin, cloxacillin, dicloxacillin. It can be concluded, therefore, that determination of the partition coefficient of a penicillin gives valuable information on the neurotoxicity to be expected. The introduction of a neurotoxicity quotient revealed that penicillins may be divided into two groups: less neurotoxic penicillins with a partition coefficient below 1.0 and highly neurotoxic penicillins with a partition coefficient above 1.0.