• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 197
  • 75
  • 39
  • 17
  • 17
  • 17
  • 17
  • 17
  • 17
  • 17
  • 7
  • 6
  • 3
  • 3
  • 3
  • Tagged with
  • 444
  • 133
  • 92
  • 69
  • 67
  • 66
  • 65
  • 58
  • 54
  • 53
  • 49
  • 48
  • 46
  • 40
  • 38
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Cereal root and stem-base fungi and effects of seed treatment fungicides

Dawson, William A. J. M. January 2000 (has links)
No description available.
2

Cinnamoylamino and methoxyfumaroylamino derivatives of epoxymorphinans - potential irreversible ligands for opioid receptors

Derrick, Ian January 1996 (has links)
No description available.
3

THE DEVELOPMENT OF INDOLEAMINE DERIVATIVES SELECTIVE FOR SUBTYPES OF SEROTONIN RECEPTORS (TRYPTAMINE, BASILAR ARTERY, ANTAGONIST, ERGOLINE, SYNTHESIS).

TAYLOR, ETHAN WILL. January 1985 (has links)
Central serotonin (5-hydroxytryptamine, 5-HT) receptors are classified into 5-HT₁ (defined by [³H]5-HT binding) and 5-HT₂ (defined by [³H]ketanserin binding). Antagonists selective for 5-HT₁ receptors or 5-HT₁(A) and 5-HT₁(B) subtypes are currently unavailable. To develop such antagonists, a study of derivatives of tryptamine (TRYP) (which are generally selective for 5-HT₁ sites) was undertaken. For amino-N-substituted TRYPs at 5-HT₁ sites, although overall potency decreases with increased N-alkyl substituent size (up to N,N-di-iPr), discrimination between subtypes of 5-HT₁ sites increases. Compounds such as N,N-di-iPr-TRYP (DIPT) and 3-(2-morpholinoethyl)indole (MEI) recognize 30% of [³H] 5-HT binding sites with high affinity (Ki<50 nM) , the rest with low affinity (Ki >4000 nM). For both the DIPT (agonist) and MEI (antagonist) series, incorporating 5-oxy substituents resulted in rank order to overall 5-HT₁ potency of 5 - OH>MeO=5H>BzO; however, the 5-oxy compounds lost the high-affinity recognition component shown by DIPT and MEI. Incorporation of an additional hetero-aromatic moiety gave amino-N-aryl substituted TRYPs (prototype AHR 1709). These were (1) highly selective for 5-HT₁(A) sites (Ki = 10 - 200 nM) over 5-HT₁(B) sites (Ki > 3000 nM), (2) potent at the 5-HT site & (3) vascular antagonists of 5-HT. Pharmacophoric differences between 5-HT₁, 5-HT₁(A) and 5-HT₂ sites were studied with rigid analogs. Racemic partial ergolines RU 27849 and RU 28306 showed diminished potency compared to TRYPs at 5-HT₁ sites, but were equipotent to homologous TRYPs at the 5-HT₂ site. At all three sites, 3-(tetrahydropyridyl)indoles (THPIs) were the most potent rigid analogs studied. A non-ergoline-like constrained analog of TRYP was synthesized and was even less potent than RU 27849 at 5-HT₁ sites, but was 4-5 times as potent as TRYP & RU 27849 at the 5-HT₂ site. While enhancing affinity for 5-HT₁ sites, the 5-MeO group can give reduced affinity for 5-HT₂ sites, thus enhancing 5-HT₁ selectivity. 5-Unsubstituted compounds may be best for 5-HT₂ selectivity. A study of 5-HT agonists in the canine basilar artery (CBA) suggests the contraction in vitro is mediated by a receptor similar to the 5-HT₁(A) binding site; 5-HT₂ receptors may also be present. Theoretical models for the production of apparent noncompetitive antagonism to 5-HT in the CBA are also examined. Syntheses of tryptamine derivatives and a conformationally constrained analog of TRYP are described.
4

A pharmacological approach to the role of smooth muscle cell proliferation during atherogenesis

Jackson, C. L. January 1989 (has links)
No description available.
5

Identification and characterisation of 5-HT←4 receptors

Grossman, Carol Jane January 1993 (has links)
No description available.
6

Nisoldipine in cardiovascular disease : comparative studies with Nifedipine

Donaldson, Kirsteen Morag January 1992 (has links)
No description available.
7

Synthetic studies towards phomactin A

Hayes, Christopher J. January 1995 (has links)
No description available.
8

Studies of the clinical pharmacology of strontium as an in vitro and in vivo marker for calcium

Moraes, Maria Elisabete Amaral January 1989 (has links)
No description available.
9

Characterisation of cannabinoid receptors and their ligands in isolated smooth muscle preparations

Gibson, Michael January 2000 (has links)
In recent years it has been shown conclusively that at least two cannabinoid receptors, termed CB1 and CB2, exist in mammalian tissues. Previous studies using the mouse isolated vas deferens have yielded results which suggest that this tissue contains cannabinoid CB1 receptors which, when activated, can mediate inhibition of electrically-evoked contractions. However, there is evidence which indicates that several of the cannabinoid receptor agonists investigated in this study may exert their effects via non-CB, or even non- cannabinoid mechanisms. In the present study, this evidence was further investigated using the cannabinoid-mediated inhibition of electrically-evoked contractions in the mouse isolated vas deferens as a model of study. The results obtained from studies using the cannabinoid receptor antagonists O-1184 and the CB1-selective SR141716A highlighted the existence of a level of agonist-dependent antagonism in mouse isolated vas deferens. This was indicated by discrepancies obtained in the pKB values of these antagonists against the compounds under investigation. In this series of investigations it was observed that the endogenous cannabinoid receptor agonist, anandamide and the capsaicin-anandamide hybrid compound, arvanil were less potently antagonised by the CB1selective antagonist/inverse agonist, SR141716A than the highly CB1-selective agonist methanandamide. Such discrepancies in pKB values indicate that anandamide and arvanil may be acting on a receptor type distinct from the cannabinoid CB1 receptor. Additionally this series of studies indicated that anandamide and WIN55212-2 were more potently antagonised when non-cumulative responses to these compounds were constructed, indicating the possibility of tolerance developing to these compounds during the construction of cumulative concentration response curves. Several, more recent studies have indicated that anandamide and its metabolically more stable analogue methanandamide may exert their actions in part through vanilloid VR1 receptors. Upon further investigation using the vanilloid VR1 receptor antagonist capsazepine in addition to SR141716A, it was observed that the effects of anandamide, methanandamide, and the capsaicin-anandamide hybrid arvanil could be attenuated by both antagonists. These results indicate that these three agonists can act through both receptor types to mediate their effects in the mouse isolated vas deferens. In this study the putative water-soluble cannabinoid receptor agonist, O-1057 was shown to inhibit the of electrically-evoked contractions in the mouse isolated vas deferens when only water was used as a vehicle. This effect was inhibited by the cannabinoid receptor antagonists O-1184 and SR141716A, providing evidence that this novel water-soluble compound was acting through the CB1 receptor. In a further study the ability of the endogenous compound palmitoylethanolamide and a range of cannabinoids which can act on the CB2 in addition to the CB1 receptor, to downregulate mast cell degranulation was investigated. It was observed that PEA, CP55940 and WIN55212-2 but not the highly CB2 receptor-selective L759656 could exert this effect. It was not possible to investigate the effects of the CB2 receptor antagonist/inverse agonist SR144528 at this time.
10

Development of in vitro smooth muscle preparations as suitable models for elucidating the mechanism of action of cannabinoids

Fernando, Susanthi R. January 1998 (has links)
The suitability of the electrically stimulated guinea-pig MP-LM preparation, mouse isolated vas deferens and urinary bladder for the study of cannabinoid receptor ligands was investigated. Cannabinoid receptor agonists produced concentration-related inhibition of the contractile responses in all three tissue preparations, demonstrating high potency, chemical- and stereo-selectivity. The rank order of the inhibitory potency of the cannabinoid agonists in all three tissue preparations correlated with their binding affinity for specific cannabinoid CB1 binding sites in rat brain tissue. These results suggested a receptor-mediated mechanism of action for cannabinoid receptor agonists via prejunctional functional cannabinoid CB1 receptors in these three models, in the absence of an antagonist. The endogenous cannabinoid receptor ligand anandamide, also produced concentration-related inhibitory effects in all three tissue preparations. However, anandamide was found to be metabolically less stable in the guinea-pig MP-LM preparation. SR141716A, a potent, CB1 selective cannabinoid receptor antagonist was found to attenuate the inhibitory effects of cannabinoid receptor agonists investigated in all three tissue preparations. This provided further evidence for a receptor-mediated mechanism of action for cannabinoid receptor ligands in these three tissue preparations. However, further studies with SR141716A suggests that, it may be acting as an inverse agonist rather than a pure antagonist in these three preparations. Finally, this study was further extended to characterise some novel cannabinoid receptor ligands in the guinea-pig ML-LM preparation and mouse isolated vas deferens.

Page generated in 0.0743 seconds