title: The long-term regulation of tyrosine hydroxylase activity in cultured sympathetic ganglia: role of ganglionic noradrenaline content.
abstract: 1 An organ culture system is described for the in vitro maintenance of superior cervical sympathetic ganglia taken from mice of any age. The relation of tyrosine hydroxylase (T-OH) activity to ganglionic noradrenaline (NA) content has been investigated under various culture conditions.2 Depolarizing stimuli such as raised extracellular potassium and ouabain evoked increases of approximately 70% in the T-OH activity of cultured ganglia over a 48 h period. Exposure to a high concentration of potassium (high K(+)) for 30 min at the start of a 48 h culture was sufficient to elicit significant increases in T-OH activity.3 Depolarization-induced rises in T-OH activity were observed after culture in the presence or absence of nerve growth factor.4 The NA content of ganglia, cultured for 48 h in the presence of high K(+), ouabain, reserpine, clorgyline and alpha-methyl-p-tyrosine, showed no constant relation to their T-OH activity.5 Dibutyryl cyclic adenosine 3'-5'-monophosphate (dibutyryl cyclic AMP) mimicked high K(+) in its effect on ganglionic T-OH activity and NA content. Theophylline enhanced the potassium effects.6 Rises in the T-OH activity of ganglia cultured in the presence of high K(+) and dibutyryl cyclic AMP were abolished if the protein synthesis inhibitors cycloheximide or actinomycin D were present in the culture medium.7 It is concluded that the link between prolonged depolarization and rises in T-OH activity does not seem to depend upon changes in ganglionic NA content. In the intact animals, trans-synaptic modulation may take the form of a depolarization-induced rise in the cyclic AMP content of sympathetic ganglionic neurones leading to nuclear mediated synthesis of T-OH.
mesh_terms: D000115:Acetylesterase / Q000378:metabolism; D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D003994:Bucladesine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D002794:Choline; D000242:Cyclic AMP / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D005725:Ganglia, Autonomic / Q000166:cytology / Q000201:enzymology* / Q000502:physiology; D005727:Ganglia, Spinal / Q000201:enzymology; D008781:Methyltyrosines / Q000494:pharmacology; D051379:Mice; D009414:Nerve Growth Factors / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects; D009638:Norepinephrine / Q000032:analysis / Q000502:physiology*; D009924:Organ Culture Techniques; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D011955:Receptors, Drug; D012110:Reserpine / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
chemical_list: D008781:Methyltyrosines; D009414:Nerve Growth Factors; D011955:Receptors, Drug; D003609:Dactinomycin; D010042:Ouabain; D003994:Bucladesine; D012110:Reserpine; D002217:Carbachol; D003513:Cycloheximide; D013806:Theophylline; D000242:Cyclic AMP; D014446:Tyrosine 3-Monooxygenase; D000115:Acetylesterase; D002794:Choline; D011188:Potassium; D009638:Norepinephrine