Targeting Topics 11q4

Galanin receptor-expressing dorsal horn neurons: Role in nociception.

Lemons LL, Wiley RG.

Neuropeptides Epub, August 2011.

This work examines the nociceptive role of galanin receptor-1-expressing neurons found in the superficial dorsal horn. 500 ng of galanin-SAP (Cat. #IT-34) was injected into the lumbar intrathecal space of rats; blank-SAP (Cat. #IT-21) was used as a control. The rats were then tested in a series of thermal nociception models. Lesioned animals were less sensitive to heat, suggesting that loss of the GalR1-expressing excitatory interneurons disrupted the pain transmission pathway.

Impaired social interaction and enhanced sensitivity to phencyclidine-induced deficits in novel object recognition in rats with cortical cholinergic denervation.

Savage S, Kehr J, Olson L, Mattsson A.

Neuroscience 195:60-69, 2011.

Forebrain cholinergic dysfunction is thought to be part of the pathophysiology of schizophrenia. The authors lesioned the cholinergic corticopetal projection of rats by infusing 0.081 µg of 192-IgG-SAP (Cat. #IT-01) into the nucleus basalis magnocellularis. The lesioned animals displayed a reduction in the duration of social interaction. When the lesioned animals were then given PCP (phencyclidine), they were no longer able to recognize a novel object. The data suggest a role of cholinergic hypofunction in the cognitive symptoms of schizophrenia.

Neural and hormonal control of food hoarding.

Bartness TJ, Keen-Rhinehart E, Dailey MJ, Teubner BJ.

Am J Physiol Regul Integr Comp Physiol 301(3):R641-55, 2011.

Hoarding of food is a commonly found behavior in humans and animals. This review discusses the neuronal and hormonal processes involved in the control of food hoarding. Several aspects of food hoarding are examined, including the role of food deprivation, environment, levels of hormones like leptin, ghrelin, and levels of peptides such as cholecystokinin. One experiment reviewed injected NPY-SAP (Cat. #IT-28) into the arcuate nucleus of rats, which changed food hoarding responses to deprivation.

Patterning of somatosympathetic reflexes reveals non-uniform organization of presympathetic drive from C1 and non-C1 RVLM neurons.

Burke PG, Neale J, Korim WS, McMullan S, Goodchild AK.

Am J Physiol Regul Integr Comp Physiol 301(4):R1112-R1122, 2011.

Some neurons in the rostral ventrolateral medulla are part of the circuitry that helps maintain blood pressure. This control is exerted through both feed-forward and reflex adjustment mechanisms. The authors used bilateral injections of anti-DBH-SAP (Cat. #IT-03, 24 ng per side) into the spinal cord of rats between T1 and T2 to better understand the organization of this circuitry. Mouse IgG-SAP (Cat. #IT-18) was used as a control. The results suggest that myelinated neurons may control baseline tone, while stressor response uses unmyelinated neurons.

Circadian Integration of Sleep/Wake and Feeding Requires NPY-Receptor Expressing Neurons in the Mediobasal Hypothalamus.

Wiater MF, Mukherjee S, Li AJ, Dinh TT, Rooney EM, Simasko SM, Ritter S.

Am J Physiol Regul Integr Comp Physiol 301(5):R1569-83, 2011.

Feeding and sleep/wake states interact rhythmically across the circadian cycle. It is suspected that the mediobasal hypothalamic area (MBH) is the site where these rhythms are integrated. The authors administered bilateral 24-ng injections of NPY-SAP (Cat. #IT-28) into the arcuate nucleus in order to eliminate NPY receptor-expressing neurons in the MBH of rats. Blank-SAP (Cat. #IT-21) was used as a control. The results indicate that these neurons are required for the interaction of feeding and sleep/wake timing.

Itch signaling in the nervous system.

Jeffry J, Kim S, Chen ZF.

Physiology (Bethesda) 26(4):286-292, 2011.

This review examines recent work done to elucidate the molecular mechanisms behind the sensation of itch. The progress of mouse genetics has allowed the field to move beyond clinical and physiological studies, toward a better understanding of the signaling involved in nonhistaminergic itch. One study discussed the use of bombesin-SAP (Cat. #IT-40) to ablate GRPr-positive neurons in the dorsal horn of mice. This lesion reduced scratching in response to pruritogens, but did not affect pain behavior – indicating that pain and itch use entirely different pathways.

The sympathetic nervous system stimulates anti-inflammatory B cells in collagen-type II-induced arthritis.

Pongratz G, Melzer M, Straub RH.

Ann Rheum Dis Epub, Sep 2011.

The sympathetic nervous system exerts anti-inflammatory effects on collagen-induced arthritis. To examine whether these effects are mediated by B-cells producing interleukin-10 (IL-10) the authors treated mice with 5-µg intraperitoneal injections of anti-DBH-SAP (Cat. #IT-03). The sympathectomy efficacy was assessed by analyzing norepinephrine levels in the spleen. The data suggest that increasing the number of IL-10 producing B cells can slow arthritis progression.

Selective ablation of mu-opioid receptor expressing neurons in the rostral ventromedial medulla attenuates stress-induced mechanical hypersensitivity.

Reynolds J, Bilsky EJ, Meng ID.

Life Sci 89(9-10):313-319, 2011.

Animals have been shown to develop hyperalgesia in response to chronic stress. Recent data has implicated the rostral ventromedial medulla (RVM) in this process. In order to clarify what role mu-opioid receptor-expressing neurons in the RVM play in rat, the authors injected 1.8 pmol of dermorphin-SAP (Cat. #IT-12) into the RVM. The rats were then subjected to a model designed to produce hypersensitivity in the hind paw. Stress-induced behavior did not change in the lesioned animals, but mechanical hypersensitivity was reduced.

Decrease of GABAergic Markers and Arc Protein Expression in the Frontal Cortex by Intraventricular 192 IgG-Saporin.

Jeong DU, Chang WS, Hwang YS, Lee D, Chang JW.

Dement Geriatr Cogn Disord 32(1):70-78, 2011.

The authors examined the use of 192-IgG-SAP (Cat. #IT-01) to establish a standardized model for dementia. Rats received several different doses of toxin in bilateral intraventricular injections. This injection method resulted in reliable memory impairment in a behavioral test, decreased GABAergic activity in the frontal cortex affecting spatial memory, and no change in the hippocampus. Using this technique, 8 µg of 192-IgG-SAP produced the optimal memory impairment.

Effect of orexin-B-saporin-induced lesions of the lateral hypothalamus on performance on a progressive ratio schedule.

Olarte Sanchez CM, Valencia Torres L, Body S, Cassaday HJ, Bradshaw CM, Szabadi E.

J Psychopharmacol Epub, Sep 2011.

It has been suggested that orexigenic neurons in the hypothalamus consist of two anatomically distinct groups. The lateral hypothalamic area group (LHA), which modulates reinforcement mechanisms; and the dorsomedial hypothalamus and perifornical area group involved in regulation of stress and arousal. Rats received bilateral 15-ng injections of orexin-SAP (Cat. #IT-20 discontinued, new production under way) into the LHA. Results from a progressive ratio model indicate that the lesioned neurons control the motor component of food-reinforced responding.

Participation of brainstem monoaminergic nuclei in behavioral depression.

Lin Y, Sarfraz Y, Jensen A, Dunn AJ, Stone EA.

Pharmacol Biochem Behav 100(2):330-339, 2011.

While the classical model states reductions in central noradrenergic activity produce depression, more recent work has indicated that higher activity in this brain region directly correlates with depression. Using a dopamine-β-hydroxlase targeted toxin to lesion the locus coeruleus of mice, along with goat-IgG-SAP (Cat. #IT-19) as a control, the authors found that treated animals showed increased resistance to depressive behavior in several tests. The results suggest that monoaminergic lesions are greatly affected by mouse strain, lesion size, and involvement of other neuronal systems.