targeted-toxins

Souza GMPR, Stornetta RL, Stornetta DS, Abbott SBG, Guyenet PG (2019) Contribution of the retrotrapezoid nucleus and carotid bodies to hypercapnia- and hypoxia-induced arousal from sleep. J Neurosci 39(49):9725-9737. doi: 10.1523/JNEUROSCI.1268-19.2019

Objective: To examine the contribution of two lower brainstem nuclei that could be implicated in CO2 and hypoxia-induced arousal.

Summary: RTN, a brainstem nucleus that mediates the effect of brain acidification on breathing, also contributes to arousal elicited by CO2 but not hypoxia.

Usage: To ablate the retrotrapezoid nucleus (RTN), SSP-SAP was administered (2.4 ng) through bilateral injections via a dorsal craniotomy.

Related Products: SSP-SAP (Cat. #IT-11)

Thorsdottir D, Cruickshank NC, Einwag Z, Hennig GW, Erdos B (2019) BDNF downregulates β-adrenergic receptor-mediated hypotensive mechanisms in the paraventricular nucleus of the hypothalamus. Am J Physiol Heart Circ Physiol 317(6):H1258-H1271. doi: 10.1152/ajpheart.00478.2019

Objective: To determine whether BDNF increases blood pressure in part by diminishing inhibitory hypotensive input from nucleus of the solitary tract (NTS) catecholaminergic neurons projecting to the PVN.

Summary: BDNF, a key hypothalamic regulator of blood pressure, disrupts catecholaminergic signaling between the NTS and the PVN by reducing the responsiveness of PVN neurons to inhibitory hypotensive β-adrenergic input from the NTS.

Usage: Bilateral NTS injections of sterile PBS (for control) or Anti-DBH-SAP (22 ng).

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

Goodman RL, He W, Lopez JA, Bedenbaugh MN, McCosh RB, Bowdridge EC, Coolen LM, Lehman MN, Hileman SM (2019) Evidence that the LH surge in ewes involves both neurokinin B–dependent and –independent actions of kisspeptin. Endocrinology 160(12):2990-3000. doi: 10.1210/en.2019-00597

Objective: To determine if NKB is involved in the RCh of the ewe in the LH surge.

Summary: NKB signaling in the RCh increases kisspeptin levels critical for the full amplitude of the LH surge in the ewe, but kisspeptin release occurs independently of retrochiamatic area (RCh) input at the onset of the surge to initiate GnRH secretion.

Usage: Bilaterial injections in the RCh of either NK3-SAP or Blank-SAP.

Related Products: NKB-SAP (Cat. #IT-63), Blank-SAP (Cat. #IT-21)

Toledo C, Andrade DC, Díaz HS, Pereyra KV, Schwarz KG, Díaz-Jara E, Oliveira LM, Takakura AC, Moreira TS, Schultz HD, Marcus NJ, Del Rio R (2019) Rostral ventrolateral medullary catecholaminergic neurones mediate irregular breathing pattern in volume overload heart failure rats. J Physiol 597(24):5799-5820. doi: 10.1113/JP278845

Objective: To investigate the potential contribution of RVLM‐C1 neurons to irregular breathing.

Summary: Findings suggest that RVLM‐C1 neurons play a pivotal role in breathing irregularities in volume overload HF, and mediate the sympathetic responses induced by acute central chemoreflex activation.

Usage: Anti-DBH-SAP was used to selectively lesion RVLM‐C1 neurons. Reduction (∼65%) of RVLM‐C1 neurons resulted in attenuation of irregular breathing, decreased apnea‐hypopnea incidence and improved cardiac autonomic control.

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

Díaz HS, Andrade DC, Toledo C, Lucero C, Arce-Álvarez A, Del Rio R (2019) Episodic stimulation of central chemoreflex elicits long-term breathing disorders and autonomic imbalance in heart failure rats. Eur Respir J 54(suppl 63):OA4936. doi: 10.1183/13993003.congress-2019.OA4936

Objective: To determine the role of CC in the development of cardiorespiratory dysfunction in a HF model.

Summary: Rats were exposed to pisodic hypercapnic stimulation (EHS) The effects of EHS in rats with heart failure were attenuated by SSP-SAP treatment.

Usage: Selective destruction of chemoreceptor neurons within the retrotapezoid nucleus (RTN) was performed via SSP-SAP injections (0.6 ng/30 nL).

Related Products: SSP-SAP (Cat. #IT-11)

Ueda H (2019) Systems pathology of neuropathic pain and fibromyalgia. Biol Pharm Bull 42(11):1773-1782. doi: 10.1248/bpb.b19-00535

Related Products: Mac-1-SAP mouse/human (Cat. #IT-06)

Tominaga M, Kusube F, Honda K, Komiya E, Takahashi N, Naito H, Suga Y, Takamori K (2019) OP11: Role of spinal cholecystokinin receptor 2 in alloknesis models. Itch 4:1-62. doi: 10.1097/itx.0000000000000030

Objective: To determine the detailed molecular and cellular mechanisms that induce alloknesis via the spinal CCK2 receptor.

Summary: Ablation of spinal CCK receptor-expressing cells by i.t. injection of CCK-SAP attenuated CCK8S-induced alloknesis in comparison with Blank-SAP control mice.

Usage: Intrathecal injection

Related Products: CCK-SAP (Cat. #IT-31), Blank-SAP (Cat. #IT-21)

Herman JP (2020) Corticolimbic stress regulatory circuits, hypothalamo–pituitary–adrenocortical adaptation, and resilience. Chen A (Ed.): Stress Resilience 291-309. Academic Press doi: 10.1016/B978-0-12-813983-7.00019-7

Summary: Review. Immunolesion of paraventricular nucleus (PVN)-projecting norepinephrine (NE) neurons with Anti-DBH-SAP attenuates acute stress reactivity (interestingly, to restraint), but it does not inhibit somatic or HPA axis responses to stress in any simple way (Flak et al.). PVN-projecting NE neurons appear to be responsible for acute responses to systemic stressors, but they do not appear to be important in mediating effects of chronic stress (Ritter et al.).

Usage: Flak et al. injected 8.82 ng of Anti-DBH-SAP into the PVN. Ritter et al. injected 42 ng into the PVN.

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

See Also:

• Flak J et al. Role of paraventricular nucleus-projecting norepinephrine/epinephrine neurons in acute and chronic stress. Eur J Neurosci 39:1903-1911, 2014.
• Ritter S et al. Immunotoxin lesion of hypothalamically projecting norepinephrine and epinephrine neurons differentially affects circadian and stressor-stimulated corticosterone secretion. Endocrinology 144(4):1357-1367, 2003.

Kiuchi MG, Chen S, Carnagarin R, Matthews VB, Schlaich MP (2019) Renal denervation for treating congenital long QT syndrome: Shortening the QT interval or modulating sympathetic tone?. Europace 21(11):1755-1756. doi: 10.1093/europace/euz251

Summary: Targeted ablation of cardiac sympathetic neurons (TACSN) through CTB-SAP injection in the left stellate ganglion (LSG), inhibited its activation, improved sympathetic remodelling, and restored cardiac autonomic balance.

See: Xiong L et al. Targeted ablation of cardiac sympathetic neurons improves ventricular electrical remodelling in a canine model of chronic myocardial infarction. Europace 20(12):2036-2044, 2018.

Related Products: CTB-SAP (Cat. #IT-14)

Walker JR, Ong A, Detloff MR (2019) Role of nociceptive afferent input on forelimb reaching and grasping behaviors in the spinal cord injured rat. Neuroscience 2019 Abstracts 572.09. Society for Neuroscience, Chicago, IL.

Summary: Individuals with spinal cord injury (SCI) suffer a loss of motor and sensory function. The current standard of care to recover fine motor control is rehabilitation focused on a combination of range of motion, aerobic, and strength training (ST). However, limited research has been conducted to determine the role of nociceptive afferent inputs from muscle on spinal plasticity and/or recovery of function. Using a rodent model of SCI strength training rehabilitation, we determined that motor training not only improves forelimb strength and fine motor function but also can modulate the development of neuropathic pain, suggesting that improvements in reaching and grasping may be due, in part, to plasticity of nociceptive afferents. To further explore this, Sprague-Dawley rats received injections of rIB4-conjugated saporin, mu p75-conjugated saporin or unconjugated (vehicle) into the cervical dorsal root ganglia unilaterally to eliminate non-peptidergic and peptidergic nociceptors. There is an uninjured cohort and a group with unilateral C5 SCI. Von Frey and Hargreaves’ tests were performed at baseline and several time points post-injection to assess the effcacy of the nociceptive elimination. Several measures of forelimb strength were recorded over time including the isometric pull task, a single pellet retrieval task and the Montoya staircase test. To confirm the depletion of peptidergic and non-peptidergic nociceptors following saporin injection and/or SCI, cervical DRGs and spinal cords were stained with antibodies against CGRP and isolectin-B4. An understanding of the role of nociceptors in spinal plasticity and functional motor and sensory recovery of SCI patients will guide future research and refine rehabilitation strategies to further improve their quality of life.

Related Products: IB4-SAP (Cat. #IT-10), mu p75-SAP (Cat. #IT-16)