The serotonergic system in Tetrahymena pyriformis.

Assays were performed to determine the presence of serotonin (5-hydroxytryptamine) in Tetrahymena pyriformis GL in two different media using two different assay procedures. Serotonin was present in quantities consistent with those observed in other varieties of protozoa. The serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) was also present, suggesting that the enzyme, monoamine oxidase (MAO), provides for serotonin deamination.

Serotonin receptors on pulmonary alveolar macrophages.

Pulmonary alveolar macrophages harvested from the albino mouse lung were shown to possess surface receptor sites capable of binding physiological concentrations of serotonin (5-hydroxytryptamine). These specific, high affinity binding sites showed temperature-dependent kinetics with a single order high affinity binding site for serotonin. The presence of serotonin receptors on pulmonary alveolar macrophages provides a basis for relating at least one mediator of pulmonary inflammatory processes and transport processes to effects upon the macrophage surface.

Alterations in hair shaft morphology in the cretin rat.

Hair samples were obtained from rats rendered hypothyroid in utero, when these animals reached 35 days of post-gestational age. The hairs were examined by scanning electron microscopy at a point on the shaft 340 mu from the bulb. All hairs, in the anagen phase, when compared, indicated that cretin rats had thinner hair shafts, more closely spaced cuticle cells, and more cuticle cells per unit of hair shaft.

Regional brain serotonin receptor changes in differentially housed mice: effects of amphetamine.

Several studies have shown that isolation-induced aggressive behavior in rodents may involve alterations in brain serotonin metabolism. The modified response, in isolated, aggressive mice, to several agents specific to serotonin receptors in the brain suggests an altered receptor availability for serotonin-like ligands. In the present study, isolated, aggressive mice showed a significant reduction in the number of serotonin binding sites in three major brain regions, and the effect of amphetamine sulfate varies according to the changes of receptors in differentially housed mice.

Estrogen binding sites on membranes from human laryngeal papilloma.

Estrogen binding sites were identified on plasma membranes from biopsy materials (N = 16) of normal human larynx; such binding was found to be specific. In tissue from 22 cases of laryngeal papilloma, membrane binding of 17-beta-estradiol was also specific. Although such binding occurred for papilloma membranes at a comparable affinity, it was clear that all membranes from the papillomatous tissue possessed a 148% greater estrogen binding capacity; there were at least 17 times more estrogen binding sites for each mg of receptor protein on papilloma membrane than for normal laryngeal epithelium.

Histaminergic mediation of the response of rat skin to topical fluorides.

The topical application of sodium fluoride to abraded rat skin produced several morphological and biochemical effects. Related to the degranulation of dermal mast cells, skin histamine concentration was increased, fluorides were absorbed into the skin, and deposited mainly kin mitochondria. Dermal histamine binding was decreased for both H1 and H2 receptors with reduced binding sites, but epidermal adenyl cyclase was activated by fluorides.