Pentylenetetrazol kindling produces a long-lasting elevation of IR-Met-Enkephalin but not IR-Leu-enkephalin in rat brain

Vindrola, Osvaldo; Asai, Miguel; Zubieta, Manuel; Talavera, Esther; Rodrı́guez, Emma; Linares, Gabriel

doi:10.1016/0006-8993(84)90548-1

Cited by 45 publications

(7 citation statements)

References 18 publications

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“…in enkephalin content following recurrent seizures (Hong et al, 1980;Vindrola et al, 1981Vindrola et al, , 1984Iadarola et al, 1986;Kanamatsu et al, 1986a, b;McGinty et al, 1986). Considered in this context, the effect of hilus lesion-induced seizures on hippocampal enkephalin is most like that of kainic acid (Gall et al, .1981b;Kanamatsu et al, 1986b;present data) in that both treatments most dramatically increase ENK-I in the mossy fiber system.…”

Section: Discussionmentioning

confidence: 99%

Seizures induce dramatic and distinctly different changes in enkephalin, dynorphin, and CCK immunoreactivities in mouse hippocampal mossy fibers

Gall

1988

J. Neurosci.

152

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Light microscopic immunocytochemical techniques were used to evaluate the influence of recurrent limbic seizure activity on the immunoreactivity for 3 neuropeptides--enkephalin, dynorphin, and cholecystokinin (CCK)--contained within the mouse hippocampal mossy fiber axonal system. Seizures were induced either by the placement of a small unilateral electrolytic lesion in the dentate gyrus hilus or by intraventricular injection of kainic acid. Both treatments induce epileptiform activity in hippocampus lasting several hours. Four days after either lesion placement or injection of 0.05–0.1 microgram kainic acid, immunoreactivity for all 3 peptides was altered throughout the intact mossy fiber system, bilaterally, but in distinctly different ways: enkephalin immunoreactivity (ENK-I) was dramatically elevated, dynorphin immunoreactivity was reduced, and CCK immunoreactivity (CCK- I) was either severely reduced or completely absent in the mossy fiber system. ENK-I was also clearly increased in other areas, including the lateral septum, the entorhinal cortex, and within the entorhinal (perforant path) efferents to temporal hippocampus. In contrast, the loss of CCK seemed restricted to the mossy fiber system in that immunostaining appeared normal in scattered hippocampal perikarya, within the dentate gyrus commissural system, as well as within other limbic structures. Four days after injections of 0.2 or 0.25 microgram kainic acid, mossy fiber ENK-I was greatly elevated, dynorphin immunoreactivity was reduced, but, unlike the situation with lower kainic acid doses, CCK-I was only modestly reduced in the mossy fibers and was clearly reduced in other hippocampal systems as well. These data indicate that epileptiform physiological activity differentially affects the regulation of 3 neuroactive peptides contained within the hippocampal mossy fiber system and suggest a mechanism through which seizurelike episodes can have a lasting influence on the operation of specific hippocampal circuitries.

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Section: Discussionmentioning

confidence: 99%

Seizures induce dramatic and distinctly different changes in enkephalin, dynorphin, and CCK immunoreactivities in mouse hippocampal mossy fibers

Gall

1988

J. Neurosci.

152

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“…The MET-enk antiserum used (Ell) was raised in rabbits to MET-enk coupled to bovine scrum albumin (BSA) as previously described [15]. Antiserum cross-reactivity was 100% with oxidized MET-enk but <0.5% with other enkephalins or endorphins.…”

Section: Characterization O F Antiseramentioning

confidence: 99%

Immunocytochemical Localization of the Neuropeptide-Synthesizing Enzyme PC1 in AtT-20 Cells

Hornby¹,

Rosenthal²,

Mathis

et al. 1993

Neuroendocrinology

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The subtilisin-like enzyme PC1 (also known as PC3) cleaves the neuropeptide precursor proopiomelanocortin at paired basic residues in transfection experiments, thus providing evidence for a critical role in precursor processing. While mRNA for this enzyme is highly enriched in neuroendocrine tissues, little is known about the tissue and subcellular distribution of the PC1 protein. This study used immunocytochemical techniques to investigate the anatomical distribution of PC1, both alone and compared to met-enkephalin (MET-enk), in AtT-20 pituicytes transfected with proenkephalin cDNA. A high density of PC1 immunostaining was observed in a small region adjacent to the nucleus and in the tips of the processes of these cells. Dual-staining immunocytochemistry of whole cells illustrated that both PC1 and MET-enk immunoreactivity were present in the tips, but PC1 was concentrated in a region adjacent to the nucleus while MET-enk punctate staining was dispersed throughout the soma. This codistribution was confirmed in semithin sections of dual-stained cells cut at 1-1.5 µm through the thickness of the cells. PC1 staining resembled that of TGN38, a marker for the trans-Golgi network. When PC1 immunocytochemistry was performed in cells that were pretreated with brefeldin A, a drug that redistributes the proximal Golgi compartments to the endoplasmic reticulum, there was a complete disruption of the defined locus of PC1 immunoreactivity. Taken together, our data indicate that (1) PC1 is concentrated in a region of the cell body resembling the trans-Golgi network and (2) both the enzyme and the processed peptide are transported to the tips of the processes. The observation of abundant PC1 within the Golgi complex supports the notion that proteolytic processing of neuropeptide precursors may be initiated in the Golgi apparatus rather than occurring solely within secretory granules.

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“…An aliquot of the KRP supernatant of stimulated neutrophils was also diluted in the same Tris-HCl buffer. Free and total immunoreactive (IR) met-enkephalin, that is, before and after the sequential enzymatic digestion with trypsin and carboxypeptidase B (22), were determined by RIA (23).…”

Section: Methodsmentioning

confidence: 99%

Proenkephalin system in human polymorphonuclear cells. Production and release of a novel 1.0-kD peptide derived from synenkephalin.

Vindrola¹,

Padros²,

Sterin-Prync³

et al. 1990

J. Clin. Invest.

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In the hematopoietic system a pluripotent stem cell generates precursors for lymphoid and myeloid lineages. Proenkephalinderived peptides were previously detected in differentiated lymphoid cells. We have studied whether the proenkephalin system is expressed in a typical differentiated cell of the myeloid lineage, the neutrophil. Human peripheral polymorphonuclear cells contain and release proenkephalin-derived peptides. The opioid portion of proenkephalin (met-enkephalincontaining peptides) was incompletely processed, resulting in the absence of low molecular weight products. The nonopioid synenkephalin (proenkephalin 1-70) molecule was completely processed to a 1.0-kD peptide derived from the COOH-terminal. This molecule was characterized in neutrophils by biochemical and immunocytochemical methods. The chemotactic peptide FMLP and the calcium ionophore A23187 induced the release of the proenkephalin-derived peptides, and this effect was potentiated by cytochalasin B. The materials secreted were similar to those present in the cell, although in the supernatant a higher proportion corresponded to more processed products. The 1.0-kD peptide was detected in human, bovine, and rat neutrophils, but the chromatographic pattern of synenkephalin-derived peptides suggests a differential posttranslational processing among species. These findings demonstrate the existence of the proenkephalin system in human neutrophils and the production and release of a novel 1.0-kD peptide derived from the synenkephalin molecule. The presence of opioid peptides in neutrophils suggests their participation in the inflammatory process, including a local analgesic effect. (J.

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Pentylenetetrazol kindling produces a long-lasting elevation of IR-Met-Enkephalin but not IR-Leu-enkephalin in rat brain

Cited by 45 publications

References 18 publications

Seizures induce dramatic and distinctly different changes in enkephalin, dynorphin, and CCK immunoreactivities in mouse hippocampal mossy fibers

Seizures induce dramatic and distinctly different changes in enkephalin, dynorphin, and CCK immunoreactivities in mouse hippocampal mossy fibers

Immunocytochemical Localization of the Neuropeptide-Synthesizing Enzyme PC1 in AtT-20 Cells

Proenkephalin system in human polymorphonuclear cells. Production and release of a novel 1.0-kD peptide derived from synenkephalin.

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