The Tyr-MIF-1 family of peptides

Reed, Gilda Werner; Olson, Gayle A.; Olson, Richard D.

doi:10.1016/0149-7634(94)90005-1

Cited by 25 publications

(24 citation statements)

References 101 publications

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“…Finally, the Nterminal tripeptide Pro-Leu-Gly-NH 2 (PLG) crosses the BBB by a partially saturable mechanism (Banks and Kastin 1994). This tripeptide has been identiÞed as a neuropeptide in laboratory studies and there is also some evidence for a PGL receptor in the rat brain (see Reed et al 1994). There are numerous reports on antidepressant-like e¤ects of PLG in animal studies (see Pignatiello et al 1989), and from a recent clinical double-blind study showing substantial antidepressant properties of this terminal side-chain tripeptide of oxytocin (Ehrensing et al 1994).…”

Section: Methodological Issuesmentioning

confidence: 98%

Oxytocin as a possible mediator of SSRI-induced antidepressant effects

et al. 1999

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The nonapeptide oxytocin is released into systemic circulation in situations of psychosocial interaction, and has been shown to be involved in mechanisms of social bonding and social recognition in laboratory studies. In view of disturbances in psychosocial relationships being a triggering factor for depression and anxiety, it is interesting to note that experimental studies have shown oxytocin to possess antidepressant- and anxiolytic-like actions. Thus. in the present study we examined effects of the SSRI citalopram (20 mg/kg i.p.) on plasma oxytocin, acutely and upon repeated administration, in adult male Sprague-Dawley rats. Plasma oxytocin, and some functionally related peptides (CCK, gastrin, somatostatin and insulin), were measured by standard radioimmunoassay techniques. Acute citalopram administration produced a statistically significant increase in plasma oxytocin and CCK levels. Administration of citalopram for 14 days did not attenuate the oxytocin-releasing effect to a challenge dose of the SSRI zimeldine (20 mg/kg s.c.), whereas CCK levels were not increased after the subchronic citalopram treatment. Thus, the SSRI citalopram produces increased plasma oxytocin levels acutely, and there appears to be no or little tolerance to this effect upon repeated administration. There were no, or variable, effects on plasma levels of gastrin, somatostatin or insulin. It is suggested that oxytocin release is an important aspect of the pharmacological actions of SSRIs, and this could be an important contributory factor for the clinical profile of this group of antidepressants with particular efficacy in disorders of psychosocial origin.

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Section: Methodological Issuesmentioning

confidence: 98%

Oxytocin as a possible mediator of SSRI-induced antidepressant effects

et al. 1999

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“…Peripherally administered chorionic gonodotrophin ( 125 I-hCG) can cross the BBB to bind selectively to LH receptors within the hippocampal formation (Lukacs et al 1995); a similar result has been obtained with personal communication). Specialised polypeptide transporter systems have been suggested (reviewed by Herbert 1986; see also Meisenberg & Simmons 1983); specific transporters have been documented for arginine-vasopressin (AVP; Zlokovic et al 1990a) and for the Tyr-MIF-1 (encephalin, dynorphin) family (Reed et al 1994). Furnished with these examples it seems prudent to assume that many blood-(and CSF-) borne ligands can gain access to binding sites in the brain, prominently in the hippocampus, either by diffusion or by facilitated transport.…”

Section: Accessibility and Functionality Of Hippocampal Receptorsmentioning

confidence: 99%

“…(Reproduced from Fig. 4 in Li & Boyages (1996) Zlokovic et al 1990a) and for the Tyr-MIF-1 (encephalin, dynorphin) family (Reed et al 1994). Furnished with these examples it seems prudent to assume that many blood-(and CSF-) borne ligands can gain access to binding sites in the brain, prominently in the hippocampus, either by diffusion or by facilitated transport.…”

Section: Accessibility and Functionality Of Hippocampal Receptorsmentioning

confidence: 99%

Hormones and the hippocampus

Lathe

2001

Journal of Endocrinology

227

161

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Hippocampal lesions produce memory deficits, but the exact function of the hippocampus remains obscure. Evidence is presented that its role in memory may be ancillary to physiological regulation. Molecular studies demonstrate that the hippocampus is a primary target for ligands that reflect body physiology, including ion balance and blood pressure, immunity, pain, reproductive status, satiety and stress. Hippocampal receptors are functional, probably accessible to their ligands, and mediate physiological and cognitive changes. This argues that an early role of the hippocampus may have been in sensing soluble molecules (termed here 'enteroception') in blood and cerebrospinal fluid, perhaps reflecting a common evolutionary origin with the olfactory system ('exteroception').Functionally, hippocampal enteroception may reflect feedback control; evidence is reviewed that the hippocampus modulates body physiology, including the activity of the hypothalamus-pituitary-adrenal axis, blood pressure, immunity, and reproductive function. It is suggested that the hippocampus operates, in parallel with the amygdala, to modulate body physiology in response to cognitive stimuli. Hippocampal outputs are predominantly inhibitory on downstream neuroendocrine activity; increased synaptic efficacy in the hippocampus (e.g. long-term potentiation) could facilitate throughput inhibition. This may have implications for the role of the hippocampus and long-term potentiation in memory. Journal of Endocrinology (2001) 169, 205-231The hippocampus and memory Attention has focused on the hippocampus in view of its likely role in memory encoding and its dysfunction in Alzheimer's disease. The hippocampal formation undoubtedly contributes to the encoding of long-term memories, but an exclusive focus on memory would be a mistake. The present review emphasises an important aspect of hippocampal function: that of responding to and governing body physiology. What follows briefly revisits the role of the hippocampus in learning and memory, and the electrophysiological correlates of memory processes, before considering how the spectrum of genes expressed in the hippocampal formation may cast light on the involvement of the hippocampus in other processes. (In this paper, 'hippocampus' and 'hippocampal formation' are used interchangably to denote the juxtaposition of the fields of the cornu ammonis with the dentate gyrus.) Memory and the hippocampusThe hippocampus, located beneath the cerebral hemispheres, resembles a large 'wishbone' (the curved Y-shaped bone in the chicken neck), but takes its name from the appearance of its arms in cross-section -the interlocking double-U formed by the tightly aligned cell bodies of ammon's horn (cornu ammonis) and the dentate gyrus -reminiscent of the shape of Hippocampus spp. ( Fig. 1; for detailed reviews of hippocampal structure see Amaral 1987, Amaral & Witter 1989. Memory problems in a patient with limbic damage (i.e. at the edge of the forebrain) were first recorded in 1898; another 60 years elapsed be...

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“…The tripeptide L-prolyl-L-leucyl-glycinamide (PLG, Fig 1), also known as melanocyte stimulating hormone release inhibiting factor (MIF-1), is an endogenous brain peptide that has been implicated in modulating dopaminergic neural transmission in the nigrostriatal pathway (Reed et al, 1994; Srivastava et al, 1988). Studies have shown that PLG does not modulate dopaminergic neurotransmission by affecting dopamine synthesis, uptake, or metabolism; rather it functions through a mechanism in which PLG renders the dopamine receptor more responsive to agonists.…”

Section: Introductionmentioning

confidence: 99%

Specific binding of photoaffinity-labeling peptidomimetics of Pro-Leu-Gly-NH2 to the dopamine D2L receptor: Evidence for the allosteric modulation of the dopamine receptor

Mann

Verma

Basu

et al. 2010

European Journal of Pharmacology

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The present study was undertaken to investigate the mechanistic role of L-prolyl-L-leucyl-glycinamide (PLG) in modulating agonist binding to the dopamine D2L receptor. Competition and displacement assays indicate that the photoaffinity-labeling peptidomimetics of PLG, 3(R)-[(4(S)-(4-azido-2-hydroxy-benzoyl) amino-2(S)-pyrrolidinylcarbonyl)amino]-2-oxo-1-pyrrolidineacetamide hydrochloride (1a) and 3(R)-[(4(S)-(4-azido-2-hydroxy-5-iodo-benzoyl)amino-2(S)-pyrrolidinylcarbonyl)amino]-2-oxo-1-pyrrolidineacetamide hydrochloride (1b) bind at the same site as PLG. Autoradiography was used to establish the covalent binding of [125I]-1b to a 51 kDa protein in bovine striatal membranes. Western blot analysis with a dopamine D2L specific antibody, in combination with autoradiography, following a two dimensional gel separation, suggested this 51 kDa protein to be the dopamine D2L receptor. Further evidence for binding of 1b to dopamine D2L was provided by samples immunoprecipitated with the D2L antibody. These samples were analyzed by western blotting in parallel with autoradiography of [125I]-1b labeled protein. Both methods revealed bands at 51 kDa. Furthermore, PLG is shown to compete with 1b for binding to the dopamine D2L receptor as determined by autoradiography, as well as competition experiments with PLG and 1a. Collectively, these findings suggest the successful development of a photoaffinity labeling agent, compound 1b, that has been used to elucidate the interaction of PLG specifically with the dopamine D2L receptor.

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The Tyr-MIF-1 family of peptides

Cited by 25 publications

References 101 publications

Oxytocin as a possible mediator of SSRI-induced antidepressant effects

Oxytocin as a possible mediator of SSRI-induced antidepressant effects

Hormones and the hippocampus

Specific binding of photoaffinity-labeling peptidomimetics of Pro-Leu-Gly-NH2 to the dopamine D2L receptor: Evidence for the allosteric modulation of the dopamine receptor

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