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Summary In the present study the distribution of specific binding sites for the GABA-A receptor agonist, 3 H-muscimol, was studied in the rat uterus using an autoradiographic technique. Specific binding sites were present in both myometrium and endometrium suggesting a dual role for GABA in this organ.

[3H]Dopamine ([3H]DA) is specifically taken up by slices of rabbit celiac artery. Corticosterone, a selective inhibitor of extraneuronal uptake processes, was found to reduce the uptake of the labelled catecholamine by about 30%. Desimipramine, an inhibitor of uptake processes in noradrenergic neurons, caused a decrease of [3H]DA uptake of about 35%. Benztropine, an inhibitor of uptake processes in dopaminergic neurons reduced [3H]DA uptake by about 30%. The neuronal uptake of [3H]DA was completely inhibited by chemical sympathectomy or by simultaneous incubation of the slices with desimipramine and benztropine. Norepinephrine had a competitive effect on [3H]DA uptake and benztropine inhibited [3H]norepinephrine uptake by 32%. The results are consistent with the existence of a double noradrenergic and dopaminergic innervation of the rabbit celiac artery.

Summary Cholinergic innervation of the blood vessels of the female reproductive system was investigated in human by the cholinesterase method. The following results were obtained: 1. The uterine and vaginal arteries are provided with a rich cholinergic innervation. 2. The ovarian, tubaric and ovarian-uterine artery are poorly innervated. 3. The ovarian and uterine vein are not provided with a cholinergic innervation.

The presence of a cholinergic innervation of the main cerebral blood vessels has been studied in the dog. Cholinergic nerve fibers are found in all examined arteries and veins, organized in two or in a single nerve plexus. The cerebral veins appear to be less innervated than arteries. The meaning of a cholinergic innervation in the cerebral circulation is discussed.

Vasoactive intestinal polypeptide (VIP) levels and distribution were studied in the penis of young-adult (3-month-old) and old (30-month-old) Wistar rats by radioimmunoassay and immunofluorescence. No significant changes in tissue VIP concentrations or distribution occurred in the penis of old rats compared to young-adult rats. The present data indicate that the age-related impairment of male sexual function is not dependent on modifications of the VIP-ergic innervation of penile tissue.

The cholinergic innervation of the aorta has been studied in some mammalian species. Cholinergic nerve fibers (CNF) are organized in the aorta of the rabbit, kid, lamb, and guinea pig in 2 plexuses. The plexuses of CNF consist of a superficial plexus localized in the adventitial layer and a deep one localized in the adventitial-medial transitional zone. Some CNF reach the outer layers of the media. In the aorta of the dog, mouse and rat CNF are organized in a single plexus localized in the adventitial layer. This nerve plexus is formed of CNF that for the most part are distributed to the vasa vasorum. The chemical sympathectomy don't alters the pattern of the cholinergic innervation of the aorta, indicating that stained CNF are parasympathetic in nature. The meaning of a cholinergic innervation of the aortic wall is discussed.

The influence of ageing on the metabolic profile of lateral ventricle choroid plexus epithelial cells from young (3-month-old) and aged (26-month-old) male Wistar rats was studied using enzyme histochemical techniques. The following enzymatic activities related to energy transduction were examined: lactate- (LDH) and succinate- (SDH) dehydrogenases; NADH 2 -tetrazolium reductase (NADHD) and α-glycerophosphate-dehydrogenase (GPDH). The intensity of enzymatic staining within single choroid plexus epithelial cells from young and old animals was assessed microphotometrically. In the choroid plexus epithelial cells of young rats NADHD was the enzymatic activity more heavily stained; cell levels of LHD and GPDH were approximately the same and SDH reactivity was less intense. In old age LDH was reduced by 9.3%, SDH was reduced by 26.1%, NADHD was reduced by 8.6% and GPDH was reduced by 3.6%. The possibility that impaired energy transduction mechanisms at the level of choroid plexus epithelium in old age may influence functional activity of the choroid plexus is discussed.

The cholinergic innervation of the human liver was studied. Slices (150--200 micrometer thick) of human liver and of the greater hepatic blood vessels (hepatic artery and vein, portal vein) were incubated in a solution of 6-hydroxydopamine (6-HDA) in order to obtain a selective degeneration of adrenergic nerves. Controls were prepared from samples incubated with buffer alone. The slices were cut on a cryostat into 15-20 micrometer thick sections and processed for the histochemical detection of cholinesterases. Cholinergic nerve fibres innervate the extra hepatic and the intrahepatic branches of the hepatic artery, the portal vein as well as the hepatic vein. Fewer cholinergic fibres innervate the hepatocytes and the hepatic sinusoids. The 6-HDA treatment does not seem to alter the pattern of the cholinergic innervation of the liver. The findings indicate the presence of a cholinergic parasympathetic innervation in the human liver.

By using fluorescence microscopy and microfluorimetric techniques, the effects of ageing and of 11 months acctyl- l -carnitine (ALCAR) treatment on lipofuscin deposition within the cytoplasm of pyramidal neurons of rat prefrontal cortex and hippocampus (CA3 field) were assessed. No lipofuscin autofluorescence was observed in the nerve cell bodies of neurons under study in young rats (3 months of age), but lipopigment had accumulated in the same nerve cells of senescent rats (22 months of age). ALCAR administration significantly reduced the accumulation of lipofuscin within pyramidal neurons of the brain areas examined.

The influence of aging on the metabolic profile of cerebellar cortex was studied in young (3-month-old), adult (12-month-old) and aged (26-month-old) male Sprague—Dawley rats using enzyme histochemical techniques. The following enzymatic activities related to energy transduction were examined: lactate-(LDH) and succinate-(SDH) dehydrogenases; NADH 2 -tetrazolium reductase (NADHD) and alpha-glycerophosphate-dehydrogenase (GPDH). The intensity of enzymatic staining within the neuropil of molecular and granular layers as well as within the cytoplasm of Purkinje neurons of young, adult and aged animals was assessed microphotometrically. In the molecular layer LSH, SDH and NADHD levels were reduced in old rats; GPDH was decreased both in adult and old animals. In Purkinje neurons no age-related changes of the enzymatic activities under study were observed. In the granular layer LDH and GPDH showed an age-dependent loss; SDH and NADHD were unchanged. The possibility that age-related changes of the enzymatic activities under study may be due to impaired energy production mechanisms and/or represent the consequence of reduced energetic needs resulting from the documented age-dependent loss of synapses in the molecular or in the granular layers of cerebellar cortex is discussed.

The effects of ageing and of 6 months of Hydergine treatment on lipofuscin deposition within the cytoplasma of pyramidal neurons of rat prefrontal cortex, hippocampus (fields CA1 and CA3) and of Purkinje neurons were assessed microfluorimetrically. No lipofuscin autofluorescence was detected in the nerve cell populations of 3-month-old rats, but lipopigment had accumulated in nerve cell bodies of 16-month-old animals and increased significantly thereafter in rats of 22 months of age. In 22-month-old rats, Hydergine administration (0.6 and 1 mg/kg p.o.) started at 16 months caused a significant dose-related decrease in lipofuscin accumulation within the cytoplasm of the various kinds of nerve cells examined.

The direct immunohistochemical detection of the potent beta-blocker (−)-alprenolol was accomplished in rat cerebellum. (−)-Alprenolol binding sites were found in Purkinje cells and in portions of the molecular and granular layers lying close to the Purkinje cells.

The pharmacological profile and the anatomical localization of Ca2+ channels of the L-type were investigated in the human pulmonary artery to identify possible mechanisms involved in the regulation of the pulmonary vascular tone. Analysis was performed on slide-mounted frozen sections of human pulmonary artery using radioligand binding assay techniques associated with light microscope autoradiography. [3H]-Nicardipine was used as ligand. Human renal and right coronary arteries also were used as systemic reference arteries. Binding of [3H]-nicardipine to sections of human pulmonary artery was time-, temperature- and concentration-dependent, saturable and reversible. In the human pulmonary artery, the apparent equilibrium dissociation constant (Kd) was 0.12+/-0.02 nM and the maximum density of binding sites (Bmax) was 38.15+/-2.25 fmol/mg tissue. Kd values were 0.3+/-0.01 nM and 0.5+/-0.02 in the human renal artery and right coronary artery respectively. Bmax values were 248+/-16 fmol/mg tissue and 173+/-9.5 fmol/mg tissue in the human renal artery and right coronary artery respectively. The pharmacological profile of [3H]-nicardipine binding to sections of human pulmonary artery was consistent with the labeling of Ca2+ channels of the L-type. It was similar in the pulmonary artery and in the human renal and right coronary arteries. Light microscope autoradiography revealed a high density of [3H]-nicardipine binding sites within smooth muscle of the tunica media of human pulmonary artery as well as of human renal and right coronary arteries. A lower accumulation of the radioligand occurred in the tunica adventitia. No specific binding was noticeable in the tunica intima. Our data suggest that human pulmonary artery expresses Ca2+ channels of the L-type sensitive to dihydropyridines. These sites have similar affinity and lower density than those expressed by systemic arteries. The presence of Ca2+ channels of the L-type in human pulmonary artery suggests that their pharmacological manipulation may be considered in the treatment of pulmonary hypertension.

The existence of a double catecholaminergic and cholinergic innervation was demonstrated in the human greater saphenous vein. Catecholamine-containing nerve fibres are organized in a network-like plexus localized at the adventitial-medial border. Acetylcholinesterase-containing nerve fibres are arranged in a plexus found at the adventitial-medial border as well. Catecholamine and acetylcholinesterase-containing nerve fibres, while localized in close apposition since they occupy the same portion of the vein, represent two distinct and independent populations of nerve fibres coming likely from the sympathetic and parasympathetic sections of the autonomic nervous system respectively. Our findings demonstrating a close relationship between catecholaminergic and cholinergic nerve fibres within the wall of the human greater saphenous vein offer morphological support to physiological and pharmacological results reported in the literature of a presynaptic control exerted by cholinergic nerves on norepinephrine release at the level of the saphenous vein.