Merck
  • Home
  • Search Results
  • The electrical activity of hippocampal pyramidal neuron is subjected to descending control by the brain orexin/hypocretin system.

The electrical activity of hippocampal pyramidal neuron is subjected to descending control by the brain orexin/hypocretin system.

Neurobiology of learning and memory (2015-02-15)
Esmail Riahi, Reza Arezoomandan, Zahra Fatahi, Abbas Haghparast
ABSTRACT

The hippocampus receives sparse orexinergic innervation from the lateral hypothalamus and expresses a high level of orexin receptor. The function of orexin receptor in the regulation of hippocampal neural activity has never been investigated. In this study, in vivo single unit recording was performed in urethane-anesthetized rats. After 15 min of baseline recording from pyramidal neuron within the CA1 region of the dorsal hippocampus, i.c.v. injection of orexin-A 0.5 nmol, SB334867 400 nmol, a selective orexin receptor 1 antagonist, saline, or DMSO, or microinjection of carbachol 250 nmol or saline into the ipsilateral lateral hypothalamus were performed using a Hamilton microsyringe, and the spontaneous firing activity continued to be recorded for 25 min. Results showed that orexin administration into the lateral cerebral ventricle excited 6 out of 8 neurons and inhibited 1 neuron. Chemical stimulation of the lateral hypothalamus by carbachol excited 9 out of 13 hippocampal neurons and inhibited 3 neurons. On the other hand, i.c.v. injection of the SB334867, caused reductions in the firing activity of 6 out of 10 neurons and increases in 4 additional neurons. It seems that orexin neurotransmission in the hippocampus mostly elicits an excitatory response, whereas blockade of orexin receptor has an inhibitory effect. Further studies need to be done to elucidate the underlying mechanism of orexin action on hippocampal neurons.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
L-Lysine monohydrochloride, SAJ special grade, ≥99.0%
Supelco
L-Lysine monohydrochloride, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
L-Lysine monohydrochloride, BioUltra, ≥99.5% (AT)
Sigma-Aldrich
Urethane, ≥99.0% (GC)
Supelco
L-Lysine monohydrochloride, certified reference material, TraceCERT®
Supelco
Urethane, analytical standard
Sigma-Aldrich
Urethane, ≥99%
Sigma-Aldrich
Dimethyl sulfoxide, meets EP testing specifications, meets USP testing specifications
Sigma-Aldrich
L-Lysine monohydrochloride, from non-animal source, meets EP, JP, USP testing specifications, suitable for cell culture, 98.5-101.0%
Sigma-Aldrich
Dimethyl sulfoxide, PCR Reagent
Sigma-Aldrich
Dimethyl sulfoxide, for molecular biology
Sigma-Aldrich
Dimethyl sulfoxide, ≥99.5% (GC), suitable for plant cell culture
Sigma-Aldrich
Dimethyl sulfoxide, Hybri-Max, sterile-filtered, BioReagent, suitable for hybridoma, ≥99.7%
Sigma-Aldrich
Dimethyl sulfoxide, BioUltra, for molecular biology, ≥99.5% (GC)
Sigma-Aldrich
Dimethyl sulfoxide, suitable for HPLC
Sigma-Aldrich
Dimethyl sulfoxide, ≥99.0%, suitable for absorption spectrum analysis
Sigma-Aldrich
Dimethyl sulfoxide, ≥99.5%
Sigma-Aldrich
Dimethyl sulfoxide, SAJ first grade, ≥99.0%
Sigma-Aldrich
Dimethyl sulfoxide, anhydrous, ≥99.9%
Sigma-Aldrich
Dimethyl sulfoxide, JIS special grade, ≥99.0%
Sigma-Aldrich
Dimethyl sulfoxide, sterile-filtered, BioPerformance Certified, meets EP, USP testing specifications, suitable for hybridoma
Sigma-Aldrich
L-Lysine monohydrochloride, reagent grade, ≥98% (HPLC)
Sigma-Aldrich
Dimethyl sulfoxide, ACS reagent, ≥99.9%
Sigma-Aldrich
Dimethyl sulfoxide, puriss. p.a., dried, ≤0.02% water
Sigma-Aldrich
Dimethyl sulfoxide, suitable for HPLC, ≥99.7%
Sigma-Aldrich
Dimethyl sulfoxide, puriss. p.a., ACS reagent, ≥99.9% (GC)
Supelco
L-Lysine hydrochloride solution, 100 mM amino acid in 0.1 M HCl, analytical standard
Supelco
Dimethyl sulfoxide, for inorganic trace analysis, ≥99.99995% (metals basis)
Dimethyl sulfoxide, European Pharmacopoeia (EP) Reference Standard
Sigma-Aldrich
Dimethyl sulfoxide solution, 50 wt. % in H2O