fluorescent-conjugates

Q: I have a few questions about the Alexa488-labeled affinity-purified NGFr antibody (Cat. #AB-N43-FLA). Is it specific to extracellular p75? Can you use it on live cells? Does it work on fixed cells? Does it cause activation of the p75 receptor (i.e., result in apoptosis or changes in axon outgrowth in neuronal cells)?

A: This product does recognize extracellular p75 in both live and fixed cells. As for the activation, that’s an interesting question. There is no evidence of 192-IgG either causing apoptosis or neurite outgrowth as far as I can see. Chandler et al. (1984) report that the antibody “partially inhibits the regeneration of neurites from primed PC12 cells,” and it enhances NGF binding. But that’s about it, despite several studies being done with PC12 cells and in vivo. We assume all this holds upon treatment with 192-IgG-SAP (Cat. #IT-01) — until the cell dies from saporin poisoning.

Chandler CE, Parsons LM, Hosang M, Shooter EM (1984) A monoclonal antibody modulates the interaction of nerve growth factor with PC12 cells. J Biol Chem 259(11):6882-6889.

Related: NGFR (192-IgG, p75) Mouse Monoclonal, Alexa488-labeled (Cat. #AB-N43-FLA)

Momiyama T, Fukazawa Y (2007) D1-like dopamine receptors selectively block P/Q-type calcium channels to reduce glutamate release onto cholinergic basal forebrain neurones of immature rats. J Physiol 580(Pt 1):103-117. doi: 10.1113/jphysiol.2006.125724 PMID: 17234695

Related Products: 192-IgG Mouse Monoclonal, Cy3-labeled (Cat. #AB-N43FL3)

Momiyama T, Zaborszky L (2006) Somatostatin presynaptically inhibits both GABA and glutamate release onto rat basal forebrain cholinergic neurons. J Neurophysiol 96(2):686-694. doi: 10.1152/jn.00507.2005 PMID: 16571735

Related Products: 192-IgG Mouse Monoclonal, Cy3-labeled (Cat. #AB-N43FL3)

Xu C, Michelsen KA, Wu M, Morozova E, Panula P, Alreja M (2004) Histamine innervation and activation of septohippocampal GABAergic neurones: Involvement of local ACh release. J Physiol 561(Pt 3):657-670. doi: 10.1113/jphysiol.2004.071712 PMID: 15486020

Related Products: 192-IgG Mouse Monoclonal, Cy3-labeled (Cat. #AB-N43FL3)

Wu M, Newton SS, Atkins JB, Xu C, Duman RS, Alreja M (2003) Acetylcholinesterase inhibitors activate septohippocampal GABAergic neurons via muscarinic but not nicotinic receptors. J Pharmacol Exp Ther 307(2):535-543. doi: 10.1124/jpet.103.052514 PMID: 12966162

Related Products: 192-IgG Mouse Monoclonal, Cy3-labeled (Cat. #AB-N43FL3)

Wu M, Xu C, Alreja M (2002) Physiological and pharmacological characteristics of the inhibitory muscarinic response in septohippocampal cholinergic neurons. Neuroscience 2002 Abstracts 35.7. Society for Neuroscience, Orlando, FL.

Summary: Septohippocampal cholinergic neurons in the MSDB provide the hippocampus with almost its entire ACh and also release ACh locally within the MSDB. The released ACh sustains activity in the GABAergic limb of the septohippocampal pathway. Septohippocampal cholinergic neurons undergo atrophy in neurodegenerative disorders associated with loss of cognition. In a recent study we demonstrated that 65% of septohippocampal cholinergic neurons are inhibited by ACh via muscarinic receptors. Because of the importance of ACh and septohippocampal cholinergic neurons in cognition, we studied the physiological and pharmacological properties of the muscarinic response in MSDB neurons. Using intracellular and whole-cell recordings, we tested the effects of muscarine on retrogradely-labeled septohippocampal cholinergic neurons in vitro in rat brain slices. The cells were labeled using the Cy3-192IgG, a selective marker of septohippocampal cholinergic neurons. Prolonged (10-15 mins) but not short (1-2 min) applications of muscarine or oxotremorine produced a marked desensitization (>50%). The muscarine-induced outward current was found to be mediated via direct as well as indirect mechanisms. It reversed at Ek and was blocked by external barium. The M2/M4 antagonist, methoctramine blocked the muscarine response in only 10% of the neurons tested and tropicamide, an M4-prefering antagonist, blocked the muscarine response in 5/5 neurons tested, suggesting possible involvement of M4 receptors.

Related Products: 192-IgG Mouse Monoclonal, Cy3-labeled (Cat. #AB-N43FL3)

Harikumar KG, Pinon DI, Wessels WS, Prendergast FG, Miller LJ (2002) Environment and mobility of a series of fluorescent reporters at the amino terminus of structurally related peptide agonists and antagonists bound to the cholecystokinin receptor. J Biol Chem 277(21):18552-18560. doi: 10.1074/jbc.M201164200 PMID: 11893747

Related Products: 192-IgG Mouse Monoclonal, Alexa488-labeled (Cat. #AB-N43FLA)

Peterson WE, Jordan LM, Brownstone RM (2001) Immunolesioning of identified motoneuron pools following intramuscular injection of the immunotoxin, 192-IgG-saporin, in neonatal rats. Neuroscience 2001 Abstracts 626.14. Society for Neuroscience, San Diego, CA.

Summary: Studies have shown that the immunotoxin, 192-IgG-Saporin, can selectively lesion p75-positive cholinergic neurons of the basal forebrain in adult rats. Here we demonstrate the novel use of 192-IgG-Saporin to induce MN loss following intramuscular (I.M.) injection in neonatal rats. Two days following I.M. injection of 192-IgG-Cy3, neonatal rats (but not adult rats or neonatal mice) had Cy3-labeled MNs. This suggests that the 192-IgG antibody and its conjugates can be internalised by receptor-mediated endocytosis and retrogradely transported to spinal motor neurons. To induce MN loss, the left hind limb musculature of anaesthetised Sprague-Dawley rats were exposed, and several muscles injected with 0.5μg of 192-IgG-Saporin (Chemicon). Right hind-limb muscles were injected with DiI. Animals were sacrificed 25 days later. Ten μm coronal sections were obtained using a cryostat and Nissl stained. The neonatal rats showed signs of a locomotor deficit 2.5 weeks post injection with 192-IgG-Saporin, which increased slightly in severity over the next week and a half. Nissl stained coronal sections of the lumbar region showed an obvious MN deficit on the 192-IgG-Saporin treated side compared to control side. The injected muscles were also severely atrophic, a not unexpected finding given that they too express p75 receptors. We conclude that 192-IgG-Saporin can be used to lesion MN pools when IM injected in neonatal rats. This model may prove useful for testing cell replacement therapies for the treatment of MN diseases like amyotrophic lateral sclerosis (ALS).

Related Products: 192-IgG Mouse Monoclonal, Cy3-labeled (Cat. #AB-N43FL3)

Camara AL, Pereira EF, Alkondon M, Randall WR, Castro NG, Cintra WM, Albuquerque EX (2001) Septal innervation of the hippocampus regulates expression α7 nicotinic receptors in CA1 and CA3 pyramidal neurons. Neuroscience 2001 Abstracts 145.1. Society for Neuroscience, San Diego, CA.

Summary: To investigate the effects of septal innervation on expression of α7 nicotinic receptors (nAChRs) in CA1 and CA3 pyramidal neurons in the hippocampus, the patch-clamp technique and confocal microscopy were applied to organotypic hippocampal cultures and septal-hippocampal co-cultures. In the co-cultures, septal fibers labeled with DiI were visualized in the hippocampus. Field stimulation of septal fibers also resulted in postsynaptic currents that could be recorded from CA1 and CA3 pyramidal neurons in the hippocampus. These currents had glutamatergic, GABAergic and cholinergic components. The latter originated most likely from the septal cholinergic neurons that were labeled in situ with the cholinergic marker Cy3-192 IgG. α7 nAChRs in the somatodendritic region of CA1 and CA3 pyramidal neurons in the hippocampus in cultures and co-cultures were activated by the α7 nAChR agonist choline, which elicited type IA currents, and were visualized by labeling with rhodamine-conjugated α-bungarotoxin (Rho-α-BGT). After 21 days in vitro, the amplitude of type IA currents was substantially smaller in pyramidal neurons in septal-hippocampal co-cultures than in hippocampal oragnotypic cultures. Labeling of the somatodendritic region of hippocampal pyramidal neurons with Rho-α-BGT was also less intense in the organotypic co-cultures than in cultures. These results suggest that functional septal innervation of the hippocampus regulates the expression of α7 nAChRs in hippocampal pyramidal neurons.

Related Products: 192-IgG Mouse Monoclonal, Cy3-labeled (Cat. #AB-N43FL3)

Gerashchenko D, Kohls MD, Greco M, Waleh NS, Salin-Pascual R, Kilduff TS, Lappi DA, Shiromani PJ (2001) Hypocretin-2-saporin lesions of the lateral hypothalamus produce narcoleptic-like sleep behavior in the rat. J Neurosci 21(18):7273-7283. doi: 10.1523/JNEUROSCI.21-18-07273.2001 PMID: 11549737

Summary: Orexin (also knows as hypocretin) peptides are produced exclusively by neurons in the lateral hypothalamus, however non-specific lesioning in this region has not produced narcoleptic-like sleep. Gerashchenko et al. use orexin-SAP (490 ng/0.5 µl; Cat. #IT-20) to specifically eliminate orexin neurons in rats. The treated rats displayed several sleep disturbances found in narcolepsy, including increased slow-wave sleep, and sleep-onset REM sleep periods. The data suggest that orexin-SAP can be used to create a model for narcolepsy in rats.

Related Products: Orexin-B-SAP (Cat. #IT-20), Saporin Goat Polyclonal, affinity-purified FITC-labeled (Cat. #AB-15APFL), Saporin Chicken Polyclonal, affinity-purified (Cat. #AB-17AP)