Disease relevance of TH

• In caudal mesenteric ganglion, in addition to Tyrosine Hydroxylase- and Neuropeptide Y-immunoreactivity, Substance P-, Vesicular Acetylcholine Transporter-, Vasoactive Intestinal Peptide-, Leu-Enkephaline- immunoreactivity were also frequently present, followed by neuronal Nitric Oxide- and Calcitonine Gene-Related Peptide- immunoreactivity [1].
• Significant and sustained reductions of myocardial catecholamine stores and activities of tyrosine hydroxylase and dopamine beta-hydroxylase have been reported in models of acutely induced ventricular hypertrophy [2].
• Activity of tyrosine hydroxylase in the striatum of newborn piglets in response to hypocapnic hypoxia [3].
• The effect of graded hypoxia induced by hyperventilation on the activity of tyrosine hydroxylase was measured in vivo by microdialysis [3].
• Activation of tyrosine hydroxylase in striatum of newborn piglets in response to hypocapnic ischemia and recovery [4].

Psychiatry related information on TH

• Pig anti-(BALB/c antinuclease) anti-idiotypic antibodies (pig anti-BALB/c Id) react only with TH of nuclease-primed BALB/c and not with B10.D2 animals [5].

High impact information on TH

• In both strains, such immunization with nuclease also leads to the production of splenic T helper cells (TH), which provide nuclease-specific help in an in vitro plaque-forming cell response to nuclease-TNP [5].
• The absence of absolute reductions in choline acetyltransferase activity in hypertrophied and failing ventricle contrasts strikingly with the previously reported reductions in tyrosine hydroxylase, which is rate limiting in sympathetic neurotransmitter biosynthesis [6].
• Dopamine-containing neurons, identified immunocytochemically by the presence of tyrosine hydroxylase, had a mean length-to-width profile of 14.9 +/- 4.4 x 11.5 +/- 3.1 microns (N = 14) [7].
• Another 50% of the nerve cell bodies contained immunoreactivity (IR) to dopamine-beta-hydroxylase (DBH), but did not have any other characteristics of noradrenergic neurons; they did not contain detectable catecholamines, or IR to dopa decarboxylase (DDC) or tyrosine (TH) hydroxylase, nor did they take up exogenous catecholamines [8].
• For comparison, the ganglion was also studied using antisera against the 2 catecholamine-synthesizing enzymes tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH) [9].

Biological context of TH

• TH inhibition was reduced upon either saturation of the double bond in the side chain or cyclization to form the dihydrobenzofuran analogs [10].
• Contrary to expectation, co-grafting of transfected GDNF-expressing HiB5 cells, a rat-derived neural cell line, tended to impair the survival of the grafts with the lowest values for graft volumes, TH-positive cell numbers, behavioral scores, and relative DOPA decarboxylase activity [11].
• These results suggest that cAMP and protein kinase C mediate the PACAP-induced TH and DBH gene expression [12].
• The membrane-associated form of TH (MTH) was activated by conditions favoring protein phosphorylation (e.g. ATP) and was inhibited by phosphatase (e.g. calf intestine phosphatase) [13].
• A series of 1-phenyl-3-amino-1,2,3,4-tetrahydronaphthalenes (1-phenyl-3-aminotetralins, PATs) previously was found to modulate tyrosine hydroxylase activity and dopamine synthesis in rodent forebrain through interaction with a binding site labeled by [(3)H]-(-)-(1R,3S)-trans-H(2)-PAT [14].

Anatomical context of TH

• TH- and TH/D beta H-IR nerves were located mostly in the capsula and connective septa of the pineal gland, and their fine varicose branches terminated in the adherent parenchyma [15].
• HPLC revealed a reduction in the concentration of dopamine (P < 0.05) and noradrenaline (P < 0.05), and Western blot analysis revealed a reduction in TH in the retinas of GR compared with control fetuses (P < 0.05) [16].
• Dual-labeling immunohistochemical studies revealed that the NPY-ir nerve fibers rarely contained immunoreactivity for tyrosine hydroxylase (TH) [17].
• Amine- and TH- containing varicosities were also present in ganglia, representing potential sites for adrenergic modulation of ganglionic neurotransmission [18].
• The mesencephalon of the young domestic pig was studied by tyrosine hydroxylase (TH) immunocytochemistry and acetylcholinesterase (AChE) histochemistry with focus on the substantia nigra (SN), the ventral tegmental area (VTA), and related areas [19].

Associations of TH with chemical compounds

• Leptin increased activating protein-1 DNA-binding activity, and this was diminished by Ro 32-0432 as well as EDTA, similar to the reduction of TH mRNA levels [20].
• Nicardipine and omega-conotoxin GVIA, each at 1 microM, were effective at inhibiting leptin-induced TH enzyme activity, TH mRNA accumulation, PKC activity, and ERK activity [20].
• However, these axons lacked IR for tyrosine hydroxylase (TH) and often ran in bundles with substance P (SP)-immunoreactive axons close to the epidermis [21].
• 5-HT-containing cells (diam: 18.2 +/- 4.4 microns; n = 161) were smaller on average than both the NADPH-d (P < 0.01) and TH-containing cells (P < 0.01) [22].
• Extrinsic nerves in the gallbladder that degenerated following chemical sympathectomy with 6-hydroxydopamine (6-OHDA), and which contained NPY, tyrosine hydroxylase (TH), and dopamine-beta-hydroxylase (DBH) immunoreactivities, formed a perivascular plexus closely associated with blood vessels [23].

Regulatory relationships of TH

• The present study also showed that H89 (a PKA inhibitor) moderately, but significantly, inhibited leptin-induced ERK and TH mRNA [20].
• Extirpation of the uterus reduced the expression of TH and induced the expression of GAL in the neurons [24].

Other interactions of TH

• In paravertebral ganglion S1, Tyrosine Hydroxylase and Neuropeptide Y were the most frequently present substances [1].
• Carotid-body-like paraganglia from the newborn pig showed cell bodies IR to TH, GAL and ENK [25].
• Several findings suggest that the expression patterns of the progesterone receptor (PR), TH and AADC overlap in the guinea pig brain [26].
• The uterus and vagina of the guinea pig have been examined, region by region, for acetylcholinesterase, tyrosine hydroxylase, dopamine beta-hydroxylase and aromatic amino acid decarboxylase activity, as well as for the neuropeptides, neuropeptide Y, vasoactive intestinal peptide, substance P, enkephalin and somatostatin [27].
• In the nasal mucosa, substance P (SP)- and tyrosine hydroxylase (TH)-like immunoreactive (SPI and THI) fibers seemed to decrease after capsaicin application [28].

Analytical, diagnostic and therapeutic context of TH

• HPLC was used to assess concentrations of catecholamines and Western blot analysis to detect total TH levels [16].
• NOS-containing neurons were identified with NADPH-diaphorase (NADPH-d) histochemistry, and monoamine-containing neurons were identified with tyrosine hydroxylase (TH) and serotonin (5-HT) immunocytochemistry [22].
• These findings also suggest that a subset of pUCM cells can differentiate into TH-positive cells within 8 weeks after transplantation into the 6-OHDA lesioned rat brain [29].
• Immunoreactivities for tyrosine hydroxylase (TH), gamma-aminobutyric acid (GABA) and, in some cases, glutamic acid decarboxylase (GAD) were detected by light and electron microscopy in axons projecting into the median eminence and pituitary gland of various mammals (rats, mice, guinea pigs, cats, rabbits and hares) [30].
• Immunosuppression did not impart a greater recovery of [18F]fluorodopa uptake, nor were the number of TH-positive graft neurons or the volumes of the grafts increased in the immunosuppressed group [11].

References