Leucine and methionine enkephalins were measured by biological assay in normal colon, adenocarcinoma of the colon, carcinoma of the caecum, and in normal and inflamed appendix. Methionine enkephalin levels in both the adenocarcinomas and inflamed appendices were significantly higher than in normal controls. No significant change occurred in leucine enkephalin levels. The caecal tumours were ana...

Opioid analgesics are used extensively in the management of pain. Although the clinically effective opioids bind with high affinity to the mu-opioid receptor, studies have suggested that the delta-opioid agonists might represent more ideal analgesic agents, with fewer side effects. A limitation to opiate effectiveness is the development of tolerance, an event that has been linked to opioid rece...

The biosynthesis and posttranslational processing of proenkephalin and the level of preproenkephalin mRNA were investigated in the mossy fiber system of the granule cells of the hippocampus in the presence or absence of a unilateral lesion of the hilus, a procedure that produces an episode of recurrent bilateral hippocampal seizures lasting several hours. Both immunocytochemistry and radioimmun...

Enkephalins and enkephalin-containing polypeptides were released from perfused bovine adrenal glands by nicotine and Ba2+, agents that release catecholamines. All the enkephalin-containing polypeptides that are normally found in the adrenal medulla were released by the two secretagogues in approximately the same proportions as are present in adrenal chromaffin granules.

Aminopeptidase activities were identified in extracts of kidney, ovotestis, head ganglia, heart and haemolymph of Aplysia californica. These enzyme preparations hydrolysed [3H][Leu]enkephalin at the Try-1-Gly-2 bond as determined by h.p.l.c. analysis of cleavage products. In all these tissues, enkephalin-degrading aminopeptidase activities were present both in membrane-bound and cytosolic fract...

Native methionine enkephalin and methionine enkephalin generated proteolytically from a larger peptide were both identified and quantified from bovine cornea by negative ion fast atom bombardment-mass spectrometry. The corneal peptides were purified initially be reverses-phase high performance liquid chromatography and identified tentatively by radioreceptor assay and/or radioimmunoassay.

We examined the role of central /tand d-opioids on both neurohormonal responses and baroreceptor reflex in conscious rabbits. Both intracerebroventricular [D-Ala,JV-Me-Phe,Gly-ol]-enkephalin, a /t-selective agonist, and [D-Ala,D-Leu]-enkephalin, a 8-selective agonist, caused dose-related increases in arterial pressure and renal sympathetic nerve activity, whereas intravenous injection of the sa...

Coexistence of regulatory peptides is reported with increasing frequency in the mammalian neuroendocrine system. We have investigated the possible presence of such coexistence in the invertebrate Lymnaea stagnalis and have found evidence for concurrence of enkephalin- and gastrin/cholecystokinin (CCK)-like peptides in identified neurosecretory neurons. Our immunocytochemical studies reveal, how...