Persistent activation of the ζ isoform of protein kinase C in the maintenance of long-term potentiation

Long-term potentiation in the CA1 region of the hippocampus, a model for memory formation in the brain, is divided into two phases. A transient process (induction) is initiated, which then generates a persistent mechanism (maintenance) for enhancing synaptic strength. Protein kinase C (PKC), a gene family of multiple isozymes, may play a role in both induction and maintenance. In region CA1 from rat hippocampal slices, most of the isozymes of PKC translocated to the particulate fraction 15 sec after a tetanus. The increase of PKC in the particulate fraction did not persist into the maintenance phase of long-term potentiation. In contrast, a constitutively active kinase, PKM, a form specific to a single isozyme (ζ), increased in the cytosol during the maintenance phase. The transition from translocation of PKC to formation of PKM may help to explain the molecular mechanisms of induction and maintenance of long-term potentiation

Inhibition of puerperal lactation by means of a single injection of bromocriptine retard

The efficacy, tolerance and acceptability of a single i.m. injection of 50 mg bromocriptine retard (in polylactic acid microspheres), given within 12 h after delivery for suppression of lactation, were investigated in 47 mothers not willing to breast-feed. Slight to moderate breast discomfort was noticed during the first postpartum days in 23% of the patients but lactation was indeed prevented in all cases and no rebound lactation occurred in any case. Only six patients exhibited at least two symptoms of mammary engorgement (congestion and pain or milk let-down): in this group, blood mean PRL levels were significantly less suppressed on postpartum days 2, 6, 21 and 28 (p < 0.05 to p < 0.001) than in the group of mothers completely free of any mammary symptoms. Slight side-effects (mostly dizziness), as mentioned at systematic request, were recorded in 34% of the patients; only 3 patients required treatment for their side-effects. Recovery of ovarian function was evident quite early (by day 28 in 72% of the patients), thus requiring early onset of contraception. © 1987.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Treatment of Turner syndrome with growth hormone (GH): evolution of somatomedin C (IGF1), procollagen III N terminal extention peptide (PC3), osteocalcin (BGP) and axial and appendicular bone mineral content (BMC)

info:eu-repo/semantics/publishe

Evidence for a new, high-molecular weight isoform of protein kinase C in rat hippocampus

We describe a new form of protein kinase C (PKC) with a molecular weight of 97 kDa, higher than the known forms of vertebrate PKC. This putative new high-molecular weight isoform, which we are calling PKC(HMW), is increased in the membrane fraction either upon application of phorbol esters or with afferent synaptic stimulation of Schaffer collaterals in hippocampal slices. The protein cross-reacts on immunoblot with affinity-purified polyclonal antiserum raised against a peptide derived from the carboxy-terminus of PKCη; it does not cross-react, however, with antiserum against the amino-terminal region of PKCη. In the tissues examined, PKC(HMW) is localized primarily in brain, in contrast to PKCη, which is found predominantly in lung and skin