targeted-toxins

Dinh TT, Flynn FW, Ritter S (2006) Hypotensive hypovolemia and hypoglycemia activate different hindbrain catecholamine neurons with projections to the hypothalamus. Am J Physiol Regul Integr Comp Physiol 291(4):R870-R879. doi: 10.1152/ajpregu.00094.2006

Summary: Hypovolemia, a decrease in blood plasma volume, results in secretion of arginine vasopressin (AVP). This work investigates the role of hindbrain catecholamine neurons in hypovolemia-induced AVP secretion. Rats were treated with bilateral 42 ng injections of anti-DBH-SAP (Cat. #IT-03) into the paraventricular nucleus of the hypothalamus, and hypovolemia was induced by blood withdrawal. Treated animals displayed severely impaired AVP response, as well as lower food intake and corticosterone secretion in response to insulin.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Madden CJ, Stocker SD, Sved AF (2006) Attenuation of homeostatic responses to hypotension and glucoprivation after destruction of catecholaminergic rostral ventrolateral medulla (RVLM) neurons. Am J Physiol Regul Integr Comp Physiol 291(3):R751-R759. doi: 10.1152/ajpregu.00800.2005

Summary: C1 neurons in the RVLM express dopamine-beta-hydroxylase (DBH). Anti-DBH-SAP (Cat. #IT-03) was used to eliminate these neurons and examine cardiovascular homeostasis in response to a physiological challenge such as hypotension. 21 ng of anti-DBH-SAP was injected into the RVLM of rats. After food and water had been removed from the cage, the lesioned animals were treated with hydralazine to reduce blood pressure. The results demonstrate that RVLM-C1 cells are involved in responses to homeostatic challenges.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Fitz NF, Gibbs RB, Johnson DA (2006) Aversive stimulus attenuates impairment of acquisition in a delayed match to position T-maze task caused by a selective lesion of septo-hippocampal cholinergic projections. Brain Res Bull 69(6):660-665. doi: 10.1016/j.brainresbull.2006.03.011

Summary: It is known that infusion of 192-IgG-SAP (Cat. #IT-01) into the medial septum of rats impairs acquisition of a delayed matching to position (DMP) T-maze task. Here, the authors evaluated whether introduction of an aversive stimulus 30 minutes prior to training would attenuate this deficit. Treated rats received 0.22 µg of 192-IgG-SAP injected into the medial septum. Data indicate that treated rats receiving an intraperitoneal injection of saline 30 minutes prior to training displayed less impairment than rats not receiving the aversive stimulus.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Li AJ, Wang Q, Ritter S (2006) Differential responsiveness of dopamine-beta-hydroxylase gene expression to glucoprivation in different catecholamine cell groups. Endocrinology 147(7):3428-3434. doi: 10.1210/en.2006-0235

Summary: This work examines how subpopulations of hindbrain catecholaminergic neurons participate in systemic glucoregulation. Rats were treated with bilateral 42 ng infusions of anti-DBH-SAP (Cat. #IT-03) into the paraventricular nucleus of the hypothalamus. Dopamine-beta-hydroxylase (DBH) expression in glucoprivic animals was then analyzed by in situ hybridization and immunohistochemistry. The data demonstrate that the ventrolateral medulla contains most of the catecholamine neurons responsive to glucoprivation.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Q: I spoke with someone from your technical service over the phone and got the impression that your product dermorphin-SAP (Cat. #IT-12) is not a retrograde and will only affect the terminals or the cells that express mu opioid receptors in the injection site in the brain. I have three questions:

1) Do you have any written document on this issue?

A: That the peptide-toxins don’t undergo retrograde transport is an example of negative data, so people haven’t really been publishing too much on that. But two articles deal specifically with it: Lappi and Wiley[1] and Bugarith et al.[2] The latter, in particular, presents solid data on the inability of the peptide ligand toxin NPY-SAP (Cat. #IT-28) to undergo retrograde transport. I don’t think we have a single example of a peptide-ligand toxin that undergoes retrograde transport. In order for a peptide-toxin to kill cells, the cell body must have the receptor and the toxin must be injected within reach of the cell body. We’ve made a mistake in not putting that in the data sheets, and will begin to change that.

2) Will dermorphin-SAP also kill terminals in the injection site or just cell bodies?

A: Let me cite for you: Tokuno et al., Efferent projections from the striatal patch compartment: anterograde degeneration after selective ablation of neurons expressing mu-opioid receptor in rats.[3] As the title implies, they address the issue of elimination of processes following cell body destruction.

3) If it also kills terminals, will it affect their remote cell bodies?

A: I’m not sure I understand this question, but that won’t stop me from trying to answer it: The situation is the contrary, because the destruction of processes comes from the action taking place in the cell body. Our experience is that once the cell body is gone, it’s just a matter of time for the process to go away. This makes these toxins a little different than others. In fact, we recommend that you wait two weeks at least to see immunohistological evidence of a toxic effect after injection of a saporin toxin in vivo. That’s how long it takes the removal process to get rid of all the antigens that you might want to use for evidence of cell loss.

Q: Can I inject NPY-SAP to destroy projections through retrograde transport?

A: Regarding NPY-SAP, a peptide-toxin, see previous response. The antibody-toxins such as 192-IgG-SAP (Cat. #IT-01) or anti-DBH-SAP (Cat. #IT-03) will undergo retrograde transport from terminals to cell bodies. Thus, you can put 192-IgG-SAP into the cortex and it will destroy neurons in the basal forebrain, because the saporin (probably the whole conjugate) is transported from the projection to the cell body. Likewise, anti-DBH-SAP in the spinal cord destroyed hindbrain catecholaminergic neurons by retrograde transport.[4] All the antibody-toxins appear to undergo retrograde transport. 

Finally, the lectin-toxins, CTB-SAP (Cat. #IT-14) and IB4-SAP (Cat. #IT-10) undergo retrograde transport, just like the native lectins do. CTB-SAP is well-described in Llewellyn-Smith et al.[5] and several others. For IB4-SAP, Vulchanova et al.[6] describe use, along with several other articles on our reference page. In addition, detailed discussions are available in the book Molecular Neurosurgery with Targeted Toxins,[7] available from Humana Press.

See: Targeted Toxins

References

1. Lappi DA et al. Entering through the doors of perception: characterization of a highly selective Substance P receptor-targeted toxin. Neuropeptides 34(5):323-328, 2000.
2. Bugarith K et al. Basomedial hypothalamic injections of neuropeptide Y conjugated to saporin selectively disrupt hypothalamic controls of food intake. Endocrinology 146(3):1179-1191, 2005.
3. Tokuno H et al. Efferent projections from the striatal patch compartment: anterograde degeneration after selective ablation of neurons expressing mu-opioid receptor in rats. Neurosci Lett 332(1):5-8, 2002.
4. Ritter S et al. Immunotoxic destruction of distinct catecholamine subgroups produces selective impairment of glucoregulatory responses and neuronal activation. J Comp Neurol 432(2):197-216, 2001.
5. Llewellyn-Smith IJ et al. Retrogradely transported CTB-saporin kills sympathetic preganglionic neurons. Neuroreport 10(2):307-312, 1999.
6. Vulchanova L et al. Cytotoxic targeting of isolectin IB4-binding sensory neurons. Neuroscience 108(1):143-155, 2001.
7. Wiley RG et al. Molecular neurosurgery with targeted toxins. , 2005. Humana Press, Totowa, New Jersey

Knox D, Berntson GG (2006) Effect of nucleus basalis magnocellularis cholinergic lesions on fear-like and anxiety-like behavior. Behav Neurosci 120(2):307-312. doi: 10.1037/0735-7044.120.2.307

Summary: Neurons in the nucleus basalis magnocellularis and substantia innominata (NBM/SI) may play a role in mediating some aspects of aversive states. The authors used 0.1 µg injections of 192-IgG-SAP (Cat. #IT-01) into the NBM/SI of rats to investigate the role these neurons play in elevated maze behavior and fear-conditioned behavioral suppression. The lesions did not affect the elevated maze behavior, but behavioral suppression was attenuated. The results indicate that NBM/SI cholinergic neurons are involved in the mediation of anxiety-like states.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Wiley RG (2006) Featured Article: Targeted toxins in pain. Targeting Trends 7(2)

Related Products: 192-IgG-SAP (Cat. #IT-01), Anti-DBH-SAP (Cat. #IT-03), Anti-SERT-SAP (Cat. #IT-23), SP-SAP (Cat. #IT-07), SSP-SAP (Cat. #IT-11), Dermorphin-SAP / MOR-SAP (Cat. #IT-12),

Read the featured article in Targeting Trends.

Nolan BC, Freeman JH (2006) Purkinje cell loss by OX7-saporin impairs acquisition and extinction of eyeblink conditioning. Learn Mem 13(3):359-365. doi: 10.1101/lm.168506

Summary: Adaptive adjustments to movements depend on cerebellar learning. This work examines the effect of a global depletion of Purkinje cells in the cerebellar cortex on delay eyeblink conditioning in rats. 15 µg of OX7-SAP (Cat. #IT-02) was infused into the left lateral ventricle 2 weeks prior to training. Purkinje cell loss in the anterior lobe and lobule HVI correlated with impaired acquisition and extinction of delay eyeblink conditioning, indicating an important role for these cells.

Related Products: OX7-SAP (Cat. #IT-02)

Frielingsdorf H, Thal LJ, Pizzo DP (2006) The septohippocampal cholinergic system and spatial working memory in the Morris water maze. Behav Brain Res 168(1):37-46. doi: 10.1016/j.bbr.2005.10.008

Summary: The authors examined whether an optimized Morris water maze test could reveal the role of the septohippocampal cholinergic system in spatial working memory. Rats were treated with bilateral 75-ng injections of 192-IgG-SAP (Cat. #IT-01) followed by acquisition of the water maze task, and two independent phases of working memory testing. Test optimization was followed by icv infusion of nerve growth factor in unlesioned animals. The data demonstrate that working memory impairments cannot be revealed by the Morris water maze test.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Parikh V, Sarter M (2006) Cortical choline transporter function measured in vivo using choline-sensitive microelectrodes: clearance of endogenous and exogenous choline and effects of removal of cholinergic terminals. J Neurochem 97(2):488-503. doi: 10.1111/j.1471-4159.2006.03766.x

Summary: A major projection of brain attention systems passes through the cholinergic portion of the cortical mantle. The authors investigated the role of high-affinity choline transporters (CHT) in the clearance of exogenous choline, as well as choline from newly released acetylcholine. 0.085 µg of 192-IgG-SAP (Cat. #IT-01) was injected into each hemisphere of the basal forebrain of rats (mouse IgG-SAP, Cat. #IT-18, was used as a control). The results demonstrate that no matter the source, increases in choline concentrations are cleared by CHT’s.

Related Products: 192-IgG-SAP (Cat. #IT-01), Mouse IgG-SAP (Cat. #IT-18)