Disease relevance of Nptx2

• Expression of NP-2 and PlxA2 mRNAs was evident in developing inner nuclear and ganglion cell layers at birth [1].
• Pregnancy increased (p < 0.01) food intake, body weight, weight gain, and food efficiency ratio (P2 vs NP2 and P1 vs NP1, respectively), but the treatment of oil included in the diets did not alter these parameters [2].

Psychiatry related information on Nptx2

• We also examined the possible role of Narp in individual differences in responding to a novel environment, a predictor of behavioural responses to psychomotor stimulant drugs including the propensity to acquire drug self-administration [3].
• Narp levels in the PFC, but not other regions, were significantly correlated with locomotor activity in a novel environment [3].

High impact information on Nptx2

• Synaptic clustering of AMPA receptors by the extracellular immediate-early gene product Narp [4].
• Narp is shown to be selectively enriched at excitatory synapses on neurons from both the hippocampus and spinal cord [4].
• Here, differential gene expression analysis using a rat complementary DNA micro array revealed neuronal activity-regulated pentraxin (Narp) as a candidate gene involved in the remodeling or progression of damaged glomeruli [5].
• RT-PCR, western and immunocytochemical analyses revealed that oligodendrocytes expressed NP1, several alternatively spliced isoforms of NP2, and a broad spectrum of both soluble (Class 3), membrane-spanning (Class 4-6), and membrane-tethered (Class 7) semaphorin ligands [6].
• In contrast, Narp expression in dendrites was minimal in these neuronal populations [7].

Chemical compound and disease context of Nptx2

• Amphetamine and cocaine do not increase Narp expression in rat ventral tegmental area, nucleus accumbens or prefrontal cortex, but Narp may contribute to individual differences in responding to a novel environment [3].

Anatomical context of Nptx2

• Immunohistochemical studies have revealed prominent expression of Narp in the mossy fiber pathway of the dentate gyrus, suggesting it may be released pre-synaptically [7].
• Immunohistochemical studies demonstrated the existence of Narp-positive cells in hippocampus, prefrontal cortex (PFC) and nucleus accumbens (NAc), with lower levels of staining in the ventral tegmental area (VTA) [3].
• Confocal microscopy analyses of rat primary hippocampal neurons revealed that PTP-NP-2 is abundantly expressed on synaptic boutons in primary neurons [8].
• Using a synthetic pentadecamer nucleotide probe, highly specific for the 5' region of rat neurophysin II (NP II), we have demonstrated the presence of AVP-NP II mRNA in the ovary of Sprague-Dawley, Long-Evans and Brattleboro rats, with an apparent molecular weight identical to that seen for hypothalamus [9].
• To demonstrate the ectopic synthesis of AVP at the pancreatic level, we explored the expression of the AVP-neurophysin-II (AVP-NP-II) precursor gene by reverse-transcriptase polymerase chain reaction (RT-PCR) and sequencing and attempted to localise the peptide by immunocytochemistry in normal rat pancreas [10].

Associations of Nptx2 with chemical compounds

• There were no differences in Narp levels in any brain region between rats treated with repeated saline injections, a single amphetamine injection (5 mg/kg), repeated amphetamine injections (5 mg/kg x 5 days), or repeated cocaine injections (20 mg/kg twice daily x 7 days) [3].
• Wild-type PTP-NP-2 showed no measurable tyrosine phosphatase activity using an in-vitro pNPP assay [8].
• NP-II prepared in our lab was judged to be a homogeneous preparation according to Sephadex G-75 gel filtration, DEAE ion exchange chromatography and polyacrylamide gel electrophoresis [11].
• Recently, postsynaptic-density 95 (PSD-95) and neuronal activity-regulated pentraxin (Narp) have been reported to be pivotal for targeting and clustering of NMDA receptors and AMPA receptors, respectively [12].
• Narp (neuronal activity-regulated pentraxin) is a secreted immediate early gene product functioning as a cluster factor for the AMPA receptor subtype of glutamate receptors [13].

Other interactions of Nptx2

• The secretion of the neuronal activity-regulated pentraxin (Narp) by hippocampal axons is restricted to contacts with interneurons [14].
• These findings, together with the presence of immunoreactive AVP in the ovaries but not hypothalami of Brattleboro rats, suggest that tissue-specific differences in AVP-NP II gene expression occur at the translational as well as transcriptional level [9].
• In this study, we demonstrate that orexin neurons display robust expression of neuronal activity-regulated pentraxin (Narp), a secreted neuronal pentraxin, implicated in regulating clustering of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors [15].

Analytical, diagnostic and therapeutic context of Nptx2

• To study the effects of psychomotor stimulants, Narp levels were quantified by Western blotting and normalized to actin [3].

References