Elwyn Griffiths

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A mechanical apparatus was used to measure hind limb resistance to flexion in rats injected with opioid peptides in the brain periaqueductal grey region (PAG). (D-Ala2, D-Leu5) enkephalin (delta agonist) and dynorphin1-8 and ethylketocyclazocine (kappa agonists) had no effects on hind limb tone. The mu agonist (D-Ala2, MePhe4, Gly-ol5) enkephalin induced(More)
High-performance liquid chromatography (HPLC) was used to investigate the degradation in vitro of several centrally-acting analogues of thyrotrophin-releasing hormone (TRH) by two subcellular fractions prepared from different areas of rat brain. Of the seven analogues studied, RX77368 (pGlu-His-(3,3'-dimethyl)-ProNH2) was the most stable analogue, showing(More)
Neurotensin is degraded by peptidases present in soluble and particulate (25000 x g) fractions of rat hypothalamus, thalamus, cortex and pituitary, the soluble fraction of the hypothalamus having the highest activity. High performance liquid chromatography and amino acid analysis were used to identify the degradation pathway. The main product in both(More)
The ability of opioids to influence rectal temperature after injection into the periaqueductal grey region (PAG) of rat brain was investigated. Both morphine and beta-endorphin caused a dose-dependent increase in rectal temperature of up to 2 degrees C. By using selective ligands of the subclasses of opiate receptor such as [D-Ala2,D-Leu5]enkephalin for(More)
With the availability of a sensitive and specific radioimmunoassay for growth hormone-release-inhibiting hormone (somatostatin or GH-RIH), it has been possible to investigate the presence of peptidase enzymes capable of inactivating this hypothalamic hormone in the hypothalamus and other brain areas of the rat. It was found that both supernatant and(More)
In the past, quality control of vaccines depended on use of a variety of testing methods to ensure that the products were safe and potent. These methods were developed for vaccines whose safety and efficacy were based on several years worth of data. However, as vaccine production technologies have developed, so have the testing technologies. Tests are now(More)
High-performance liquid chromatography (HPLC) has been used to separate and identify the metabolites formed from thyrotrophin-releasing-hormone (TRH) and its hyperactive analogue, (3Me-His)TRH, by subcellular fractions from rat cortex, hypothalamus and thalamus. Deamidation by the proline endopeptidase and formation of histidylproline diketopiperazines by(More)
Neurotensin (NT) and carbachol both caused hypothermia when injected into the periaqueductal grey area (PAG) of rat brain. Atropine prevented carbachol- but not NT-induced hypothermia. NT-induced hypothermia was unaffected by various neurotransmitter agonists and antagonists in the PAG. Both NT antibodies and thyrotrophin releasing hormone prevented(More)