Werner A. Klee

Opiate receptors as regulators of adenylate cyclase.

This monograph reports on the progress of Nirenbergs neuroblastoma research. The authors find that morphine inhibits enzymatic activity and enzyme production levels. Additionally, hybrid cells show that the number of opiate receptors mediates inhibition of morphine. Results suggest that because drugs may act as enzyme inducers, recovery from the addicted state requires return of adenylate cyclase activity to normal levels.

Identification of a Mr 58 000 glycoprotein subunit of the opiate receptor.

A M r 58 000 subunit of the opiate receptor has been identified using tritiated fentanyl isothiocyanate, a potent opiate alkylating reagent with specificity for the δ‐opiate receptor subclass. The subunit is alkylated in the presence of dextrorphan but not levorphanol. The specifically labelled protein was retained on columns of immobilized wheat germ agglutinin and is therefore presumably a glycoprotein. Partial purification of the M r 58 000 opiate receptor subunit from neuroblastoma × glioma NG108‐15 hybrid cell membranes is described.

The role of α-lactalbumin in lactose synthetase

The A protein of lactose synthetase can catalyze lactose formation from UDP-galactose and glucose even in the absence of α-lactalbumin but only poorly because of a very high Km for glucose. α-Lactalbumin decreases the Km for glucose as well as that for N-acetylglucosamine (NAG). Depending only on the substrate concentration α-lactalbumin can stimulate disaccharide formation or inhibit this process both with NAG and with glucose. The affinities of the two sugars are such that under normal assay conditions, in the presence of α-lactalbumin, the concentration of glucose is optimal for lactose synthesis whereas that of NAG is inhibitory.

Effect of dehydration on the endogenous opiate content of the art neuro-intermediate lobe

The relationship of endogenous opiate peptides of rat neuro-intermediate lobe to the release of neurohypophysial peptides has been investigated. Both dehydrated rats, with increased oxytocin and vasopressin release, as well as rats homozygous for hypothalamic diabetes insipidus (DI) of the Brattleboro strain, with increased oxytocin release, showed significantly decreased levels of pituitary opiate peptides. We suggest that neuro-intermediate lobe opiate peptides may modulate the release of neurohypophysial antidiuretic peptides.

A new class of nonionic detergents with a gluconamide polar group

Detergents containing either a cholic acid, a deoxycholic acid, or an octanoic acid-like hydrophobic moiety and a bisgluconamidopropyl polar group were synthesized. Extinction coefficients, partial specific volumes, critical micelle concentrations, and aggregation numbers were determined for each of the detergents. The two bile acid derivatives are capable of solubilizing functional opiate receptor, while the octanoic acid derivative is not.

The synthesis of methionine by enzymic transmethylation: VII. Existence of two separate homocysteine methylpherases on mammalian liver

Abstract In addition to the enzyme thetin-homocysteine methylpherase, rat and horse livers contain a second enzyme capable of catalyzing the methylation of homocysteine to form methionine. This enzyme differs from thetin-homocysteine methylpherase (a) in its substrate specificity which is much more favorable to the naturally occurring methyl donor betaine; (b) in its behavior towards calcium phosphate and alumina gels, and Sephadex G-75; (c) in its intracellular distribution; and (d) in its concentration in neonatal and regenerating rat liver. The physiological significance of the two homocysteine methylpherases is discussed.

Exorphins: peptides with opioid activity isolated from wheat gluten, and their possible role in the etiology of schizophrenia

Endogenous opioid peptides, the endorphins (including enkephalin) are extremely potent substances which exert their effect at concentrations in the nanomolar range (Hughes et al., 1975; Lord et al., 1977; Klee, 1977). Furthermore, even though endorphin receptors are very specific, many structural variations are tolerated, albeit often with some loss of potency (Terenius et al., 1976a; Ling and Guillemin, 1976; Chang et al., 1976; Coy et al., 1976; Schiller et al.; 1977, Agarwal et al., 1977; Beddell et al., 1977). Nevertheless, peptides with as little as 1 per cent of the activity of enkephalin will still be potent and could have profound pharmacological effects. Food proteins which happen to contain the appropriate peptide sequences, related to but not necessarily identical with those of the enkephalins could therefore be a natural source of opioid peptides. Such peptides might logically be called ‘exorphins’, since they are exogenously derived substances with morphine-like activity. We have found exorphin activity in pepsin digests of wheat gluten, a protein known to be arimar factor in the pathology of celiac disease, and postulated by Dohan (1966a) to be also involved in the etiology of schizophrenia.

Synthesis of leucine enkephalin derivatives: Structure-function studies

Abstract The solid phase synthesis of highly purified [Leu 5 ] enkephalin and of seven derivatives including [Ala 2 ,Leu 5 ]-, [Ser 2 ,Leu 5 ]-, [Ser 3 ,Leu 5 ]-, [Aba 2 ,Leu 5 ]-, and [des-Gly 2(3) ,Leu 5 ]enkephalins are reported, and their morphine-like activities in neuroblastoma x glioma cell homogenates were measured. Changes at the 2, 3, and 5 positions of the enkephalin provided analogues which were all less active than [Leu 5 ] enkephalin. The results are discussed in terms of recently suggested conformational structures for the enkephalin peptides. No melanocyte stimulating activity was observed for [Leu 5 ] enkephalin, [Ala 2 ,Leu 5 ]enkephalin, or [Ser 2 ,Leu 5 ] enkephalin.

Antagonist potency and receptor binding

Abstract Receptor binding constants, using 3H-dihydromorphine and P 2 fraction of rat brain homogenate, have been determined for 28 narcotic antagonists. A good correlation (R = 0.92) has been obtained between the binding constants and antagonist potency as determined by Kosterlitz et al. Using the guinea pig ileum preparation. It appears that the systems used in the correlation are useful in determining s similarities or dissimilarities of guinea pig ileum and rat brain receptors.

Endogenous Opiate Peptides

The discovery, within the past year or so, of the endogenous opiate peptides (Hughes et al., 1975b) has captured the imagination of pharmacologists and chemists alike and led to a remarkable burst of scientific productivity. I try in this chapter to review this work in a coherent, if highly personal, way, with the sad realization that much of what I say may be outdated by the time this volume is in print. The statement by Collier quoted above is to my knowledge the first explicit recognition of the likelihood that endogenous ligands for the opiate receptor must exist, and was made at the International Congress of Pharmacology in San Francisco in 1972. Within three years, the endogenous opiate peptides were isolated and characterized, and further progress will undoubtedly be even more rapid. Nevertheless, a review of the field at this time may be of some value to those who are not specialists in opiates. For this reason, I have also chosen, by way of introduction, to review briefly some aspects of the mechanism of action of morphine as it has developed over the past several years.