Synaptic innervation of sympathetic ganglion cells in the bullfrog.

The synaptic innervation of the ganglion cells in the ninth and tenth paravertebral sympathetic ganglia of the bullfrog was investigated by histochemical and electron microscopic techniques and by intracellular recording. The neurons were unipolar and most ganglion cells were innervated by a single preganglionic axon. The preganglionic fiber stained for acetylcholinesterase and was observed to spiral around the axon hillock of the ganglion cell before arborizing and making synaptic contact with the neuron. Most synapses were located on the soma near the axon hillock region, with features typical for cholinergic junctions. The axosomatic location of the synapses was manifested physiologically by a decrease in membrane resistance (increased conductance) at the peak of the fast EPSP (excitatory postsynaptic potential) and by a demonstrable reversal potential for the fast EPSP.

Identification of small intensely fluorescent (SIF) cells as chromaffin cells in bullfrog sympathetic ganglia.

Small intensely fluoresent (SIF) cells were investigated in the ninth and tenth paravertebral sympathetic ganglia of the bullfrog using histochemical and electron microscopic techniques. Fluorescence histochemistry revealed that clusters of SIF cells are sparsely distributed in the ninth and tenth ganglia; the clusters were usually located in the vicinity of blood vessels. Fluorescent processes were not observed emanating from SIF cells. The clusters stained positively for the chromaffin reaction indicating that SIF cells are chromaffin cells. Ultrastructurally, the SIF-chromaffin cells in the sympathetic ganglia appeared virtually identical to the chromaffin cells in the adrenal gland; this includes two cell types that appear morphologically the same as the epinephrine and norepinephrine containing chromaffin cells in the adrenal gland. Efferent synapses from the SIF-chromaffin cells in sympathetic ganglia to sympathetic ganglia to sympathetic neurons were not observed. The SIF-chromaffin cells in bullfrog sympathetic ganglia did not have the morphological characteristics of interneurons; it is suggested that they may function as extra-adrenal chromaffin tissue.

Autonomic innervation and plasma estradiol-17beta and progesterone levels in rats with subcutaneous ovarian autografts.

Ovaries were removed from female rats and immediately autografted into a subcutaneous pouch in the flank in order to quantitate the relationship of graft re-innervation, steroid secretion and vaginal smear pattern. Animals were killed at thre time periods: three days after grafting, on the first day a cornified vaginal smear appeared and at the first metestrus. In addition, control animals were killed at metestrus. Plasma samples were obtained from all rats and analyzed for estradiol-17beta and progesterone concentration by radioimmunoassay. At the first day of vaginal cornification after grafting, plasma estradiol-17beta (45.8+/-4.0 pg/ml) was elevated in comparison to controls at metestrus (24.0+/-2.6 pg/ml), but plasma progesterone (21.5+/-4.0 ng/ml) was not different (30.6+/-1.7 ng/ml). Subsequently, at the first metestrus following grafting, plasma estradiol-17beta (23.0+/-3.5 pg/ml) was comparable to control values. In contrast, progesterone was decreased (17.5+/-1.9 ng/ml). A definite correlation was detected between the vaginal smear and plasma levels of steroid hormones in the castrated female rat with subcutaneous ovarian autographs Histochemical techniques were used to study the adrenergic and cholinergic innervations of grafts three days after grafting, at the first day of vaginal cornification, and at the first metestrus. No correlation was shown between density of adrenergic or cholinergic innervation and plasma levels of estradiol-17beta and progesterone or onset of a cycling vaginal smear.

GABA catabolism: localization of succinic semialdehyde dehydrogenase in brain motor and sensory nuclei.

The localization of brain succinic semialdehyde dehydrogenase, a specific gamma-aminobutyric acid degradative enzyme, could potentially yield valuable information concerning the function of the enzyme. Application of a new histochemical technique for this enzyme has revealed characteristic patterns of neuronal staining that are contsistent within embryologically and functionally similar nuclei of the brainstem of the rat.