Pharmacological and immunological characterization of the Leu5 analogue of human beta-endorphin

[Poison in the filter: implementing detoxification procedures in schizophrenia]

In the history of psychiatry a variety of "blood detoxification" procedures have repeatedly been used to treat schizophrenic disorders under the assumption of autointoxication. In the 1970s this led to the use of dialysis. In addition to the historical classification of this therapeutic approach, particularly the protagonists active in the German Democratic Republic (GDR) as well as the dimension of research and science policy are highlighted. Despite the relatively low success rate of the treatment overall, the question of which patients actually had a positive response to the treatment arises. This seemed to primarily be the case for young patients in whom acute catatonic symptoms occurred. From today's perspective there are striking indications that the patients who were successfully treated at that time could belong to the group of autoimmune encephalitis, as they are known today. Autoimmune encephalitis and specifically anti-N-methyl-D-aspartate receptor encephalitis (NMDA-R) demonstrate a characteristic clinical progression with the frequent occurrence of psychiatric symptoms, which also include catatonic symptoms. These can occur in a variety of mental and neurological disorders but are often associated with schizophrenia. To primarily reduce the risk of diagnostic errors, they should initially be considered as non-specific from a diagnostic perspective. In the future, correlating immunological and psychopathological changes may help to delineate groups for whom specific therapies are particularly suitable.

Immunocytochemical localization of beta-endorphin (lipotropin C-fragment) in the developing rat spinal cord and hypothalamus

Immunocytochemical studies have been performed on rat spinal cord and hypothalamus during development, using an antibody to beta-endorphin. Specific immunoreactivity was demonstrated in histological sections of spinal cord, in ventral and dorsal horn cells and nerve fibres, in the meningeal layer, the ependymal lining of the central canal, and in the endothelium of the ventral spinal artery and other blood vessels. beta-Endorphin immunoreactivity was also distributed widely in neurones, central and peripheral nerve fibres, and in non-neuronal cells in cultures of spinal cord tissue explanted from rat embryos 7--10 days before birth. Immunofluorescence disappeared abruptly after the 28th postnatal day in vivo, and in the fourth week of incubation of embryonic spinal cultures. In contrast, cultures of the ventral diencephalic (hypothalamic) region of embryonic brain at the same gestational age showed a characteristically different pattern of beta-endorphin immunoreactivity which persisted for more than 7 weeks. The results provide evidence for the biosynthesis of a beta-endorphin-like peptide in rat spinal cord during development. The biosynthesis terminates at an early stage both in vivo and in vitro, suggesting that control of the biosynthesis is intrinsic to spinal cord tissue and possibly to the peptide-producing cells themselves.

beta-Endorphin: characteristics of binding sites in rabbit spinal cord

The interaction of human beta-endorphin with binding sites in rabbit spinal cord has been characterized. The stereospecific high-affinity binding sites are concentrated in the dorsal half of the spinal cord. Scatchard analysis of the binding data shows heterogeneity of the binding sites that can be resolved into two populations with apparent dissociation constants of 3.0 (+/-2.0) X 10(-10) and 3.3 (+/- 0.5) X 10(-9) M. Sodium ions decrease the binding of human beta-endorphin to spinal cord to the same extent as found in rat brain. The ability of several opiates and opioid peptides to inhibit the binding of human beta-endorphin is also presented.

Beta-Endorphin: dissociation of receptor binding activity from analgesic potency

Biological activities of synthetic camel beta-endorphin and human beta-endorphin (beta h-EP) have been measured by the radioreceptor binding assay, using [Tyr27-3H]-beta h-EP as the primary ligand and by the tail-flick test for analgesic potency. Four synthetic analogs of beta h-EP, namely [Gly31]-beta h-EP-Gly-NH2, [Gly31]-beta h-EP-Gly-Gly-NH2, [Gln8,Gly31]-beta h-EP-Gly-Gly-NH2, and [CH3(CH2)4NH231]-beta h-EP, have also been assayed by the same procedures. Results indicate a clear dissociation of radioreceptor binding activity from analgesic potency.

Psychiatric implications of endorphin research

The revelation that opium-like substances are constitutional body elements is surely one of the major biological advances of the decade. The notion that the brain contains an inbuilt supply of opioid chemicals has been particularly seductive to the psychiatrist. It seems to offer a key to understanding, and therefore manipulating, the cerebral substrates for somatic pain, drug addiction and psychic discomfort. At a time when research effort in this area is increasing logarithmically, I present here a selective and personal view of certain aspects of endorphin research which have been claimed to be psychiatrically relevant. For detailed accounts of the background and breadth of endorphin research the reader is directed to other more extensive recent reviews (Kosterlitz and Hughes, 1977; Guillemin, 1978; Snyder, 1978; Watson et al, 1979; Hughes, 1979). The term endorphin will be used in the generic sense to include the specific Endorphins (such as β-Endorphin) and the enkephalins (Leu- and Met-)—see figure.