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At least 721 records · Page 40Linked to original sources
PubMed1993

Species differences in the pharmacology of the 5-hydroxytryptamine2 receptor: structurally specific differentiation by ergolines and tryptamines.

Species differences in the recognition of a series of ergolines by the 5-hydroxytryptamine2 (5-HT2, serotonin2) receptor were investigated in four species, the rat, pig, squirrel monkey and human. In pig frontal cortical membranes the initial studies showed that the ergolines gave shallow displacement curves against [3H]ketanserin binding. The component of [3H]ketanserin binding having low affinity for the ergolines was determined to be the result of [3H]ketanserin binding to alpha-1 adrenergic receptors. Thus, in all subsequent assays prazosin was used to mask [3H]ketanserin binding to alpha-1 adrenergic receptors. Examination of a series of ergolines revealed a distinct pattern in the species selectivity. Compounds that were unsubstituted at the N1 position of the ergoline nucleus showed higher affinity for the pig, squirrel monkey and human 5-HT2 receptors than for the rat. Conversely, compounds that had an N1-isopropyl substituent showed higher affinity for the rat receptor compared to the pig, squirrel monkey and human 5-HT2 receptors. For example, LY53857, a widely used 5-HT2 antagonist, has an isopropyl substituent at position N1 of the ergoline nucleus and exhibited a 4- to 5-fold higher affinity for the rat 5-HT2 receptor, whereas its N1-unsubstituted homologue, LY86057, had more than 10-fold higher affinity for the pig, squirrel monkey and human 5-HT2 receptors. Similar results were seen with three additional ergoline pairs, each having different substituents at the C8 position compared to LY53857. Even an N1-substitution on LY53857 as small as a methyl group, LY108742, resulted in the compound having higher affinity for the rat 5-HT2 receptor compared to the other species.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2005

Catalytic enantioselective addition of indoles to arylnitroalkenes: an effective route to enantiomerically enriched tryptamine precursors.

A new valuable catalytic protocol for the preparation of synthetically useful beta-indolyl nitro compounds bearing benzhydryl stereocenters is presented. The combined use of catalytic amounts of a commercially available chiral [SalenAlCl] complex and pyridine allowed, for the Friedel-Crafts alkylation reaction of indoles with aromatic nitro-olefins to be carried out in good yields and enantioselectivity (up to 63% ee).

Journal Article↗
PubMed1989

Chronic immobilization stress: evidence for decreases of 5-hydroxy-tryptamine immunoreactivity and for increases of glucocorticoid receptor immunoreactivity in various brain regions of the male rat.

Male rats were exposed to severe 14 day immobilization stress. Body weight, body temperature, food and water intake, behavioral parameters, and serum corticosterone levels were measured during and after the stress period. On the 7th day after cessation of stress the experimental animals together with the control rats were taken to immunocytochemical analysis involving morphometry and microdensitometry of tyrosine hydroxylase (TH), 5-hydroxytryptamine (5-HT), various neuropeptide, and glucocorticoid receptor (GR) immunoreactivities (IRs) in a large number of regions of the central nervous system. In addition, adrenocorticotropic hormone (ACTH) IR was analyzed in the pituitary gland. Seven days following cessation of the chronic stress food intake, total locomotion and forward locomotion had been restored to normal. Serum corticosterone levels appeared to remain increased even 6 days following cessation of the chronic immobilization stress, probably caused by increased release of ACTH. Paraventricular corticotropin releasing hormone (CRF) IR was negatively correlated with the pituitary ACTH IR, indicating that the increase in ACTH release was produced by an increased release of CRF from the hypothalamus. The major immunocytochemical change observed 7 days after cessation of stress was a disappearance of 5-HT IR in the 5-HT cell groups B1, B2, B3, and B7. 5-HT IR in nerve terminals was only affected in the dorsal horn, where 5-HT IR was increased in the substantia gelatinosa. GR IR was found to be significantly increased in monoaminergic cell groups: serotoninergic B7, dopaminergic A12, and noradrenergic A1, A2, and A6. A trend for a reduction of TH IR was observed in nigral DA cells associated with significant reductions in TH IR in striatal DA nerve terminals. Finally, increases in 5-HT and substance P (SP) IR were found in the nerve terminals of the substantia gelatinosa of the cervical spinal cord in the stress group. In the present experimental model evidence has been obtained for a maintained activation of the hypothalamic-pituitary-adrenal axis as evaluated 7 days after cessation of severe chronic immobilization stress. The reduction of 5-HT IR in various 5-HT cell groups indicates a reduction of 5-HT synthesis, which may also be associated with reduced 5-HT release from the nerve terminals, since no depletion was observed in terminal regions and in one case an increase in 5-HT IR was noted (substantia gelatinosa).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗