Rat brain

In 1966, the name was proposed (5) for receptors blocked by the at that time known antihistamines. It was also speculated that the other actions of histamine were likely to be mediated by other histamine receptors. The existence of the H2 receptor was accepted in 1972 (6) and the receptor was recognized in rat brain in 1983 (7). receptors in the brain appear to be involved in the feedback control of both histamine synthesis and release, whereas release of various other neurotransmitters, eg, serotinin (5-HT), dopamine, noradrenaline, and acetylcholine, is also modulated (8) (see Neuroregulators). 

Thyroid hormone receptors (THRs) are subdivided intoa and P types, each having two isoforms. In rat brain, THR, mRNA is present in hippocampus, hypothalmus, cortex, cerebellum, and amygdala. Thyroxine (l-T (284) and triiodothyronine (l-T ) (285) are endogenous ligands for the THRs. TRIAC (286) is a THR antagonist. Selective ligands for PPARs have yet to be identified (Table 16). 

Steroid Hormones and Neurosteroids. Steroids (qv) can affect neuroendocrine function, stress responses, and behavioral sexual dimorphism (78,79) (see Steroids). Mineralocorticoid, glucocorticoid, androgen, estrogen, and progesterone receptors are localized in the brain and spinal cord. In addition to genomic actions, the neurosteroid can act more acutely to modulate the actions of other receptors or ion channels (80). Pregnenolone [145-13-17, ( ) dehydroepiandosterone [53-43-0] C H2 02 (319) are excitatory neurosteroids found in rat brain, independent of adrenal... 

A two-site immunometric assay of undecapeptide substance P (SP) has been developed. This assay is based on the use of two different antibodies specifically directed against the N- and C-terminal parts of the peptide (95). Affinity-purified polyclonal antibodies raised against the six amino-terminal residues of the molecule were used as capture antibodies. A monoclonal antibody directed against the carboxy terminal part of substance P (SP), covalently coupled to the enzyme acetylcholinesterase, was used as the tracer antibody. The assay is very sensitive, having a detection limit close to 3 pg/mL. The assay is fiiUy specific for SP because cross-reactivity coefficients between 0.01% were observed with other tachykinins, SP derivatives, and SP fragments. The assay can be used to measure the SP content of rat brain extracts. 

Acetylcholine is a neurotransmitter at the neuromuscular junction in autonomic ganglia and at postgangHonic parasympathetic nerve endings (see Neuroregulators). In the CNS, the motor-neuron collaterals to the Renshaw cells are cholinergic (43). In the rat brain, acetylcholine occurs in high concentrations in the interpeduncular and caudate nuclei (44). The LD q (subcutaneous) of the chloride in rats is 250 mg/kg. 

Angiotensin (from rat brain) [70937-97-2 M 1524.8. Purified using extraction, affinity chromatography and HPLC [Hermann et al. Anal Biochem 159 295 1986],... 

Dipeptidyl aminopeptidase (from rat brain) [9031-94-1] [EC 3.4.11.10]. Purified about 2000-fold by column chromatography on CM-cellulose, hydroxylapatite and Gly-Pro AH-Sepharose. [Imai et al. J Biochem (Tokyo)93 431 1983.]... 

Adenylyl Cyclases. Table 3 Nucleoside inhibitors of adenylyl cyclase. Assays were with a detergent-dispersed adenylyl cyclase from rat brain and were with 100 pM 5 ATn and 5 mM MnCI2 as substrates... 

Fritschy J-M, Mohler H (1995) GABAA-receptor heterogeneity in the adult rat brain differential regional and cellular distribution of seven major subunits. J Comp Neurol 14 154-94... 

Molecularly, mammalian voltage-dependent sodium channels are composed of the main pore forming a subunit and smaller auxiliary (3 subunits. The rat brain sodium channel contains the 260-kD a subunit, the 36-kD (31 subunit and the 33-kD (32 subunit. The subunit stoichiometry is a (31 (32 = 1 1 1. 

The two examples given here will be the determination of flavones in grapefruit juice and the measurement of histamine in rat brain. 

A weighed quantity of rat brain was treated with an appropriate volume of 0.4 M perchloric acid and homogenized. The homogenate was then centrifuged for 20 min at 20,000 rpm and 1 ml of the supematent liquid removed. 

Chromatogram Showing Histamines from Rat Brain Tissue... 

Guidon, P.T.J. Hightower, L.E. (1986). The 73 kD heat shock cognate protein purified from rat brain contains nonesterified palmitic and stearic acids. J. Cell. Physiol. 128,239-245. 

Devane WA, Dysarz FA, Johnson MR, et al Determination and characterization of a cannabinoid receptor in rat brain. Mol Pharmacol 34 605—613, 1988 D Souza DC, Kosten TR Cannabinoid antagonists a treatment in search of an illness. Arch Gen Psychiatry 58 330—331,2001... 

Although the exact mechanisms of action of LSD and tryptamine-related compounds are incompletely understood (Freedman 1987), there is convincing evidence relating the psychotomimetic effects of these substances to serotonergic transmission in the brain (Davis 1987 Freedman 1987 McCall 1986 Nichols 2004). An antagonism of 5-HT in the rat brain is sufficient to cause a fourfold decrease in the threshold dose ofLSD (Appel and Freedman 1964). 

Buckholtz NS, Zhou DF, Freedman DX, et al Lysergic acid diethylamide (LSD) administration selectively downregulates serotonin2 receptors in rat brain. Neuropsychopharmacology 3 137-148, 1990... 

Gobaille S, SchleefC, HechlerV, etal Gamma-hydroxybutyrate increases tryptophan availability and potentiates serotonin turnover in rat brain. Life Sci 70 2101-2112, 2002... 

Compounds that affect activities of hepatic microsomal enzymes can antagonize the effects of methyl parathion, presumably by decreasing metabolism of methyl parathion to methyl paraoxon or enhancing degradation to relatively nontoxic metabolites. For example, pretreatment with phenobarbital protected rats from methyl parathion s cholinergic effects (Murphy 1980) and reduced inhibition of acetylcholinesterase activity in the rat brain (Tvede et al. 1989). Phenobarbital pretreatment prevented lethality from methyl parathion in mice compared to saline-pretreated controls (Sultatos 1987). Pretreatment of rats with two other pesticides, chlordecone or mirex, also reduced inhibition of brain acetylcholinesterase activity in rats dosed with methyl parathion (2.5 mg/kg intraperitoneally), while pretreatment with the herbicide linuron decreased acetylcholine brain levels below those found with methyl parathion treatment alone (Tvede et al. 1989). 

Hasan M, Khan NA. 1985. Methyl parathion induced dose related alteration in lipid levels and lipid peroxidation in various regions of rat brain and spinal cord. Indian J Exp Biol 23 141-144. 

Khan NA, Hasan M. 1988. Dose-related neurochemical changes in the levels of gangliosides and glycogen in various regions of the rat brain and spinal cord following methyl parathion administration. Exp Pathol 35 61-65. 

Kumar MVS, Desiraju T. 1992. Effect of chronic consumption of methyl parathion on rat brain regional acetylcholinesterase activity and on levels of biogenic amines. Toxicology 75 13-20. 

Abalis IM, Eldefrawi ME, Eldefrawi AT. 1986. Effects of insecticides on GABA-induced chloride influx into rat brain microsacs. J Toxicol Environ Health 18 13-23. 

Ansari RA, Husain K, Gupta PK. 1987. Endosulfan toxicity influence on biogenic amines of rat brain. 

Lakshmana MK, Raju TR. 1994. Endosulfan induces small but significant changes in the levels of noradrenaline, dopamine and serotonin in the developing rat brain and deficits in the operant learning performance. Toxicology 91(2) 139-50. 

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