Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The phloroglucinol derivative hyperforin has been recently shown to be a major antidepressant component in the extract of Hypericum perforatum. Experimental studies clearly demonstrated its activity in different behavioral models of depression. Moreover clinical studies linked the therapeutic efficacy of Hypericum extracts to their hyperforin content, in a dose-dependent manner. The molecular mechanism of action of hyperforin is still under investigation. Hyperforin has been shown to inhibit, like conventional antidepressants, the neuronal uptake of serotonin, norepinephrine and dopamine. However, hyperforin inhibits also the uptake of gamma-aminobutyric acid (GABA) and L-glutamate. The uptake inhibition by hyperforin does not involve specific binding sites at the transporter molecules; its mechanism of action seems to be related to sodium conductive pathways, leading to an elevation in intracellular Na(+) concentration. Other additional mechanisms of action of hyperforin, involving ionic conductances as well synaptosomal and vesicular function, have been suggested. In addition to its antidepressant activity, hyperforin has many other pharmacological effects in vivo (anxiolytic-like, cognition-enhancing effects) and in vitro (antioxidant, anticyclooxygenase-1, and anticarcinogenic effects). These effects could be of clinical importance. On the other hand, the role of hyperforin in the pharmacological interactions occurring during Hypericum extract therapy must be fully investigated. Hyperforin seems to be responsible for the induction of liver cytochrome oxidase enzymes and intestinal P-glycoprotein. Several pharmacokinetic studies performed in rats and humans demonstrated oral bioavailability of hyperforin from Hypericum extract. Only recently a new chromatographic method for detection of hyperforin in the brain tissue has been developed and validated. Taking into account the chemical instability of hyperforin, current efforts are directed to the synthesis of new neuroactive derivatives.
 ...
PMID:Role of hyperforin in the pharmacological activities of St. John's Wort. 1549 71

The inhibitory effects of gamma-aminobutyric acid (GABA)ergic neurotransmission in the periaqueductal gray matter (PAG) are mediated, at least partly, by metabotropic GABA(B) receptor subtypes whose cellular and subcellular localization is still unknown. We performed immunohistochemical experiments with an antibody against GABA(B) receptor subtype 1a/b (GABA(B)R(1a/b)) by using light and electron microscopy. On light microscopy, GABA(B)R(1a/b) immunoreactivity (IR) was in all columns, defined by cytochrome oxidase histochemistry. Neuropil labeling was strongest in the lateral portion of dorsolateral PAG. Labeled neurons, albeit not numerous, were in ventrolateral, dorsal, and medial subdivisions and were sparser in dorsolateral PAG. Labeling was mostly on the soma of PAG neurons. Sometimes GABA(B)R(1a/b) IR spread along proximal dendrites; in these cases bipolar neurons were the most common type. On electron microscopy, GABA(B)R(1a/b) IR was mainly on dendrites (54.92% of labeled elements) and axon terminals (21.90%) making synapses with labeled and unlabeled postsynaptic elements. Presynaptic labeling was also on unmyelinated and myelinated axons (overall 8% of all labeled elements). Postsynaptically, GABA(B)R(1a/b) IR was at extrasynaptic sites on dendritic shafts; spines were always unlabeled. On axon terminals, GABA(B)R(1a/b) IR was on extrasynaptic membranes and sometimes on presynaptic membrane specializations. Of the labeled elements, 13.03% elements were distal astrocytic processes (dAsPs) surrounding both symmetric and asymmetric synapses whose pre- and postsynaptic elements were often labeled. Immunoreactive dAsPs were around the soma and dendrites of both labeled and unlabeled neurons. These findings provide insights into the intrinsic PAG organization and suggest that presynaptic, postsynaptic, and glial GABA(B) receptors may play crucial roles in controlling PAG neuronal activity.
 ...
PMID:Cellular and subcellular localization of the GABA(B) receptor 1a/b subunit in the rat periaqueductal gray matter. 1792 69

Fipronil is a neurotoxic insecticide that inhibits the gamma-aminobutyric acid receptor and can affect gustative perception, olfactory learning, and motor activity of the honeybee Apis mellifera. This study determined the lethal dose (LD50) and the lethal concentration (LC50) for Africanized honeybee and evaluated the toxicity of a sublethal dose of fipronil on neuron metabolic activity by way of histochemical analysis using cytochrome oxidase detection in brains from worker bees of different ages. In addition, the present study investigated the recovery mechanism by discontinuing the oral exposure to fipronil. The results showed that mushroom bodies of aged Africanized honeybees are affected by fipronil, which causes changes in metabolism by increasing the respiratory activity of mitochondria. In antennal lobes, the sublethal dose of fipronil did not cause an increase in metabolic activity. The recovery experiments showed that discontinued exposure to a diet contaminated with fipronil did not lead to recovery of neural activity. Our results show that even at very low concentrations, fipronil is harmful to honeybees and can induce several types of injuries to honeybee physiology.
 ...
PMID:Effects of sublethal dose of fipronil on neuron metabolic activity of Africanized honeybees. 2322 48

The distribution of the immunoreactivity for gamma-aminobutyric acid (GABA), choline acetyltransferase (ChAT), calcium-binding proteins (CaBPr) and histochemistry of cytochrome oxidase activity (CO) was studied in turtles (Testudo horsfieldi, Emys orbicularis) isthmal complex of visual nuclei. Magnocellular nucleus (IMc) was shown to reveal mainly the strongly stained GABA-, parvalbumin (PV)-ir neurons and CO-positive cells, as well as variable both in number and degree of intensity of ChAT-, cal- bindin (CB)-, and calretinin (CR)-ir cells. After the local tracer injection into the optic tectum GABA-ir neurons containing also retrograde label were found in IMc. The most caracteristic of the parvocellular nucleus (IPc) was the content of strongly stained ChAT-ir neurons, dense GABA-ir and CO-active terminal fields, as well as the neurons variable by the amount and the degree of immunoreactivity for CaBPr and GABA. Principal similarity in these features in the turtle IMc and IPc and of those in the avian isthmal nuclei of the same name allows suggesting their homology and consequently the same participation in selective processing of the visual information flow. The comparison with lower vertebrates confirms the evolutionary conservatism of visual isthmal complex among vertebrates and the existence of its progressive differentiation in the process of evolution.
 ...
PMID:[Turtle isthmic complex of visual nuclei: immunohistochemical study of gamma-aminobutyric acid, choline acetyltransferase, calcium-binding proteins and cytochrome oxidase activity]. 2578 21

We studied the cellular organization of the piriform network [comprising the piriform cortex (PC) and endopiriform nucleus (EP)] of the ferret (Mustela putorius)-a highly excitable region prone to seizures-and, more specifically, the distribution and morphology of different types of gamma-aminobutyric acid (GABA)ergic neurons, and the distribution and ratio of glutamatergic and GABAergic boutons, and we compared our findings to those in primary visual area 17, and secondary areas 18 and 19. We accomplished this by using cytochrome oxidase and immunohistochemistry for mature neuronal nuclei (NeuN), GABAergic neurons [glutamic acid decarboxylase-67 (GAD67), calretinin (CR) and parvalbumin (PV)], and for excitatory (vesicular glutamate transporter 1; VGluT1) and inhibitory (vesicular GABA transporter; VGAT) boutons. In the ferret, the cellular organization of the piriform network is similar to that described in other species such as cats, rats and opossums although some differences also exist. GABAergic immunolabeling showed similarities between cortical layers I-III of the PC and visual areas, such as the relative distribution of GABAergic neurons and the density and area of VGluT1- and VGAT-immunoreactive boutons. However, multiple differences between the piriform network and visual areas (layers I-VI) were found, such as the percentage of GABAergic neurons with respect to the total number of neurons and the ratio of VGluT1- and VGAT-immunoreactive boutons. These findings are relevant to better understand the high excitability of the piriform network.
 ...
PMID:Distribution of GABAergic Neurons and VGluT1 and VGAT Immunoreactive Boutons in the Ferret (Mustela putorius) Piriform Cortex and Endopiriform Nucleus. Comparison With Visual Areas 17, 18 and 19. 3121 94


<< Previous 1 2 3