Endogenous opiates and behavior: 2004

Bodnar, Richard J.; Klein, Gad

doi:10.1016/j.peptides.2005.06.010

Cited by 107 publications

(61 citation statements)

References 1,220 publications

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“…It may be protective to neurons and oligodendroglia (Hauser et al 2005). It takes part in the transmission of information concerned with the interaction of feeding and maintenance of energy balance (Baile et al 1983), and regulation of fluid homeostasis (Bodnar and Klein 2005). In untreated or salt loaded rats, only a few Dyn-immunoreactive neurons are found in the PVN and SON, but their number markedly increases after colchicine pretreatment (Meister et al 1990b).…”

Section: Son and Pvn Principal Osmoregulatory Neuropeptidesmentioning

confidence: 99%

Response of Substances Co-Expressed in Hypothalamic Magnocellular Neurons to Osmotic Challenges in Normal and Brattleboro Rats

et al. 2008

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The intention of this review is to emphasize the current knowledge about the extent and importance of the substances co-localized with magnocellular arginine vasopressin (AVP) and oxytocin (OXY) as potential candidates for the gradual clarification of their actual role in the regulation of hydromineral homeostasis. Maintenance of the body hydromineral balance depends on the coordinated action of principal biologically active compounds, AVP and OXY, synthesized in the hypothalamic supraoptic and paraventricular nuclei. However, on the regulation of water-salt balance, other substances, co-localized with the principal neuropetides, participate. These can be classified as (1) peptides co-localized with AVP or OXY with unambiguous osmotic function, including angiotensin II, apelin, corticotropin releasing hormone, and galanin and (2) peptides co-localized with AVP or OXY with an unknown role in osmotic regulation, including cholecystokinin, chromogranin/secretogranin, dynorphin, endothelin-1, enkephalin, ferritin protein, interleukin 6, kininogen, neurokinin B, neuropeptide Y, vasoactive intestinal peptide, pituitary adenylate cyclase-activating polypeptide, TAFA5 protein, thyrotropin releasing hormone, tyrosine hydroxylase, and urocortin. In this brief review, also the responses of these substances to different hyperosmotic and hypoosmotic challenges are pointed out. Based on the literature data published recently, the functional implication of the majority of co-localized substances is still better understood in non-osmotic than osmotic functional circuits. Brattleboro strain of rats that does not express functional vasopressin was also included in this review. These animals suffer from chronic hypernatremia and hyperosmolality, accompanied by sustained increase in OXY mRNA in PVN and SON and OXY levels in plasma. They represent an important model of animals with constantly sustained osmolality, which in the future, will be utilizable for revealing the physiological importance of biologically active substances co-expressed with AVP and OXY, involved in the regulation of plasma osmolality.

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Section: Son and Pvn Principal Osmoregulatory Neuropeptidesmentioning

confidence: 99%

Response of Substances Co-Expressed in Hypothalamic Magnocellular Neurons to Osmotic Challenges in Normal and Brattleboro Rats

et al. 2008

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“…The opioid receptors and their ligands were identified mostly in the central nervous system, but they also occur in peripheral organs and tissues Bodnar and Klein 2005). More recently, the presence of both the opioid peptides and the opioid receptors in various cancer cell types was reported (for review, see Fichna and Janecka 2004).…”

Section: Introductionmentioning

confidence: 99%

Opioid-induced regulation of µ-opioid receptor gene expression in the MCF-7 breast cancer cell line

Gach

Piestrzeniewicz

Fichna

et al. 2008

Biochem. Cell Biol.

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The aim of the study was to investigate the presence of opioid receptor types in human breast adenocarcinoma MCF-7 cells and to characterize the changes in MOR expression induced by opioid agonist and antagonist treatment. We have shown that all three types of opioid receptors, but predominantly MOR, are expressed in MCF-7 cells. Selective MOR agonists, morphine, endomorphin-1, and endomorphin-2 downregulated MOR mRNA levels in a concentration- and time-dependent manner, but the effect produced by endomorphins was much stronger. Downregulation was blocked by the opioid antagonist naloxone. Naloxone alone produced a slight increase in MOR gene expression. Immunoblotting with antiserum against MOR-1 confirmed these results at the protein level. The results of our study indicate that, in MCF-7 cells, MOR gene expression is downregulated by opioid agonists and upregulated by opioid antagonists. We propose that the opioid-induced regulation of MOR mRNA expression is mediated by reduced binding of the transcription factors NFkappaB and AP-1 to the promoter region on the MOR gene.

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“…Preferential activation of one signalling cascade over another has previously been shown to occur for cannabinoid receptors (CB 1 ) (Glass & Northup, 1999), serotonin receptors (Berg et al, 2001) and adrenergic receptors (Eason et al, 1994;Kukkonen et al, 2001). The opioid receptors are good candidates for the investigation of agonist-specific receptor conformations because only four different receptors have been cloned with the potential to bind opioid ligands, yet there are at least 10 different endogenous opioid agonists (Bodnar & Klein, 2004). A possible explanation for the need of surplus endogenous ligands is for differential activation of the receptors.…”

Section: Introductionmentioning

confidence: 99%

Differential activation of G‐proteins by μ‐opioid receptor agonists

Saidak

Blake-Palmer

Hay

et al. 2006

British J Pharmacology

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1 We investigated the ability of the activated m-opioid receptor (MOR) to differentiate between myristoylated G ai1 and G aoA type G a proteins, and the maximal activity of a range of synthetic and endogenous agonists to activate each G a protein.2 Membranes from HEK293 cells stably expressing transfected MOR were chaotrope extracted to denature endogenous G-proteins and reconstituted with specific purified G-proteins. The G a subunits were generated in bacteria and were demonstrated to be recognised equivalently to bovine brain purified G a protein by CB 1 cannabinoid receptors. The ability of agonists to catalyse the MORdependent GDP/[35 S]GTP g S exchange was then compared for G ai1 and G aoA . 3 Activation of MOR by DAMGO produced a high-affinity saturable interaction for G aoA (K m ¼ 2071 nM) but a low-affinity interaction with G ai1 (K m ¼ 116712 nM). DAMGO, metenkephalin and leucine-enkephalin displayed maximal G a activation among the agonists evaluated. Endomorphins 1 and 2, methadone and b-endorphin activated both G a to more than 75% of the maximal response, whereas fentanyl partially activated both G-proteins. 4 Buprenorphine and morphine demonstrated a statistically significant difference between the maximal activities between G ai1 and G aoA . Interestingly, DAMGO, morphine, endomorphins 1 and 2, displayed significant differences in the potencies for the activation of the two G a . Differences in maximal activity and potency, for G ai1 versus G aoA , are both indicative of agonist selective activation of G-proteins in response to MOR activation. 5 These findings may provide a starting point for the design of drugs that demonstrate greater selectivity between these two G-proteins and therefore produce a more limited range of effects.

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Endogenous opiates and behavior: 2004

Cited by 107 publications

References 1,220 publications

Response of Substances Co-Expressed in Hypothalamic Magnocellular Neurons to Osmotic Challenges in Normal and Brattleboro Rats

Response of Substances Co-Expressed in Hypothalamic Magnocellular Neurons to Osmotic Challenges in Normal and Brattleboro Rats

Opioid-induced regulation of µ-opioid receptor gene expression in the MCF-7 breast cancer cell line

Differential activation of G‐proteins by μ‐opioid receptor agonists

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