Liisa Räisänen

A THIOCHOLINE-LEAD FERROCYANIDE METHOD FOR ACETYLCHOLINESTERASE

The principle employed in the thiocholine-copper ferrocyanide method of Karnovsky and Roots has been adopted for the development of a similar procedure in which lead, complexed with Tris-acetate buffer, is used as the trapping agent for the ferrocyanide ion, formed by the preferential reduction of ferricyanide by thiocholine released enzymatically from acetylthiocholine. The resulting colloidal, faintly yellowish white precipitate, Pb2Fe(CN)6, can be viewed directly by light or phase contrast microscopy, or more easily following its conversion to PbS. The method has been shown to produce extremely fine localization of acetylcholinesterase in the cat superior cervical and stellate ganglia and at the motor end plates of mouse intercostal muscle.

IN VITRO RELEASE AND UPTAKE OF NORADRENALINE IN THE RAT IRIS

Publisher Summary This chapter presents the study of the in vitro release and uptake of noradrenaline in the rat iris. Albino rats of the Sprague–Dawley strain were used. Incubation of the iris with up to 100 μg/ml of noradrenaline (NA) for 2–4 h caused but a slight or no increase in the fluorescence intensity of the adrenergic nerve net, whether, or not 1 mg/ml of glucose and up to 1 mg/ml of ATP were present. Incubation in solutions containing 100 μg/ml of DOPA, TA, dopamine (DA), A, or 5-HT caused in 1.5–2 h a marked decrease in the fluorescence intensity of the nerve fibers. While formaldehyde does not render TA fluorescent, the other compounds employed are demonstrable with the present technique, although a longer exposure is necessary to convert A into a fluorescent compound. An increase in the fluorescence intensity of the tissues between the nerve fibers was indeed observed, but only after incubation in DOPA, or DA, while the nerve fibers had become almost indistinguishable.

CYTOPHOTOMETRIC STUDY ON THE CHROMAFFIN REACTION, THE IODATE REACTION AND FORMALIN-INDUCED FLUORESCENCE AS INDICATORS OF ADRENALINE AND NORADRENALINE CONCENTRATIONS IN THE ADRENAL MEDULLA

Variable depletion of adrenal catecholamines was caused in rats by injections of reserpine and muscular work. The intensities of the chromaffin reaction, the iodate reaction and formalin-induced fluorescence in adrenal sections were measured by cytophotometry and compared with chemically determined concentrations of adrenaline and noradrenaline in the adrenal medulla. A close correlation was observed between the optical density of the chromaffin reaction and the total catecholamine concentration, as well as between the intensity of the formalin-induced fluorescence, the optical density of the iodate reaction and the noradrenaline concentration.

CHANGES INDUCED BY PROLONGED ADMINISTRATION OF NICOTINE IN THE DISTRIBUTIONS OF CHOLINESTERASES AND ACID PHOSPHATASE IN THE ADRENAL MEDULLA OF THE RAT

PROLONGED administration of nicotine causes a pronounced hyperplasia of the adrenal medulla in the rat, as was demonstrated by STAEMMLER (1935) over 20 years ago. E m u 6 (19550) observed that this hyperplasia is associated with about a five-fold increase in the noradrenaline content of the adrenal without any significant change in the adrenaline content. Moreover, the volume of the noradrenalinecontaining medullary parenchyma, as demonstrated histochemically by formalininduced fiuorescence (ERANKO, 1951, 1952, 19550ib), increased in proportion to the noradrenaline content, while there was no significant change in the volume of the admalinecontaining medullary tissue. Earlier work has indicated that the activities of enzymes such as acid phosphatase (Aph) (ERANKO, 1951, 1952) and cholinesterases (ALLEN, ERANKO and HUNTER, 1958; ERANK~, 1958, 1959) are different in the regions of the two types of adrenomedullary cells of the rat. It seemed therefore to be of interest to investigate histochernically these enzymes in the hyperplastic adrenal medulla of nicotine-injected rats. The present study shows that nicotine treatment brings about marked changes in the distributions and activities of these enzymes.

Effect of denervation on histochemically demonstrable acetylcholinesterase and non-specific cholinesterase in the rat adrenal.

1957). Recent histochemical work has shown that the distributions of acetylcholinesterase (ACE) and non-specific cholinesterase (nsChE) in the adrenal medulla of the rat somewhat differ from each other (ERANKO, 1958, 1959). The present work demonstrates that denervation causes a loss of A C E activity, but does not much affect the activity of nsChE in the rat adrenal. TSXJDZIMURA, 1934; HOLLINSHEAD, 1936; YOUNG, 1939; HILLARP, 1946; STOHR,