sfn2006

Masawaki A, Sugiyo S, Shimoda T, Sakai Y, Watanabe M, Moritani M, Yoshida A, Niwa H, Takemura M (2006) Formalin-induced pain-related responses in rat lacking neurokinin-1 receptor neurons in the trigeminal nucleus caudalis. Neuroscience 2006 Abstracts 50.8. Society for Neuroscience, Atlanta, GA.

Summary: This study examines the effect of intra cisterna magna injection of substance P (SP) conjugated to saporin (SP-Sap; 5µM, 5µl) on formalin-induced pain-related behavior (PRB; face scrubbing behavior ) and c-Fos expression in the trigeminal nucleus caudalis (SpVc). In SP-Sap-treated rats, the numbers of NK-1-immunoreactive neurons in lamina I of the SpVc decreased compared with those in saline- or blank Sap-treated rats. The mean numbers ±SEM of PRB /5 min at the first phase (0-5 min after For injection) were 58.2±19.2 in the SP-Sap-treated rats, 115.6±14.0 in the saline treated rats and 86.9±45.7 in the blank-Sap-treated rats. The numbers at the quiescent period (5-10 min) were 45.2±26.3 in the SP-Sap- treated rats, 93.6±26.5 in the saline treated rats and 69.4±16.3 in the blank-Sap-treated rats. These at the former second phase (10-50 min) were 58.1±22.3 in the SP-Sap-treated rats, 133.6±26.1 in the saline treated rats and 95.8±29.6in the blank-Sap-treated rats. These at the latter second phase (55-90 min) were 7.0±5.6 in the SP-Sap-treated rats,13.7±12.4 in the saline treated rats and 10.4±22.5 in the blank-Sap-treated rats. These results indicate that formalin-induced nociceptive responses in the SP-Sap-treated rats are reduced.

Related Products: SP-SAP (Cat. #IT-07), Blank-SAP (Cat. #IT-21)

Martin MM, Schultz MD, Winter SS, Wallace DG (2006) Selective cholinergic lesions of the medial septum disrupt dead reckoning-based navigation. Neuroscience 2006 Abstracts 66.10. Society for Neuroscience, Atlanta, GA.

Summary: Recent investigations using selective lesion techniques have suggested that the septohippocampal cholinergic system may not be critical for spatial orientation. These studies employ spatial tasks that provide the animal with access to both allothetic and idiothetic cues; therefore, the spared performance may reflect intact spatial orientation or compensatory mechanisms associated with one class of spatial cues. The present study examined the contribution of the septohippocampal cholinergic system to spatial behavior by examining performance in foraging tasks in which cue availability was manipulated. Female Long-Evans rats were either given a sham surgery or a selective medial septum/ vertical limb of the diagonal band cholinergic lesion using the neurotoxin 192 IgG-saporin. Rats were then trained to find food pellets randomly located on an open field which they then carried back to a visible home base (“cued”) to eat. Once they became proficient at returning to their home base location, cued training was alternated with probes. The three probes included 1) replacing the visible home base with a hidden home base to measure ability to use cues not associated with the home base (“uncued”); 2) moving the hidden home base to a new location to pit use of allothetic cues against idiothetic cues (“reversal”); and 3) testing under completely dark conditions thereby limiting access only to idiothetic cues (“dark”). Although both groups could use allothetic cues as evidenced by intact performance on cued and uncued probes, rats with compromised septohippocampal cholinergic systems were impaired during the reversal and dark probes. These observations are consistent with a selective role for the septohippocampal cholinergic system in idiothetic cue processing necessary for dead reckoning based navigation.

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

Fadel J, Frederick-Duus D, Butts R (2005) Orexin lesions block food-related increases in cortical acetylcholine release. Neuroscience 2005 Abstracts 644.8. Society for Neuroscience, Washington, DC.

Summary: Hypothalamic orexin (hypocretin) neurons influence and coordinate arousal, state-dependent behavior, feeding and metabolic processes. Orexin fibers are seen in close proximity to choline acetyltransferase (ChAT)-positive magnocellular somata in portions of the basal forebrain and intrabasalis administration of orexin A increases cortical acetylcholine (ACh) release, suggesting that orexin inputs to the basal forebrain may be important for biasing attentional resources toward stimuli related to underlying homeostatic challenges. Here, we mildly food-deprived rats and trained them to associate an environmental stimulus (darkness) with presentation of palatable food. Microdialysis in these animals showed that the darkness stimulus, with or without accompanying food presentation, produced a robust increase in cortical ACh release. A subset of animals received unilateral administration of the immunotoxin orexin B-saporin (OxB-SAP; 350 ng/0.5 μl) or vehicle into the lateral hypothalamus and perifornical area. OxB-SAP produced a substantial (70-80%) ipsilateral loss of orexin-immunoreactive cells and a corresponding decrease in orexin fiber density in the basal forebrain. OxB-SAP did not alter the number or basal forebrain neurons showing ChAT-immunoreactivity and produced only mild (approximately 15%) loss of melanin-concentrating hormone cells. Basal cortical ACh release was unaffected in lesioned animals, but OxB-SAP lesions abolished increases in cortical ACh release associated with the food-paired stimulus. These data indicate that orexin inputs to the basal forebrain are required for food anticipatory-related increases in cortical ACh release. Orexins appear to be important components of the neural pathways by which interoceptive cues related to homeostasis recruit forebrain attentional systems.

Related Products: Orexin-B-SAP (Cat. #IT-20)