Biomedical subjects

F Amenta

Publications and source records attributed to F Amenta.

At least 37 records · Page 2Linked to original sources

PubMed1996

Age-dependent changes in the expression of dopamine receptor subtypes in human peripheral blood lymphocytes.

The pharmacological profile and the density of dopamine D3 and D5 receptor subtypes expressed by human peripheral blood lymphocytes of subjects of different ages (ranging from 20 to 75 years) were assessed using radioligand binding techniques. Dopamine D3 receptor was assayed with [3H]7-hydroxy-N,N-di-n-propyl-2-aminotetraline ([3H]7-OH-DPAT) as a ligand. Dopamine D5 receptor was assayed using [3HIR]-(+)-(-chloro-2,3,4,5, tetrahydro-5-phenyl-1H-3-benzazepin-al-hemimaleate) ([3H]SCH 23390) as a ligand. The affinity and the pharmacological profile of [3H]7-OH-DPAT and [3H]SCH 23390 at dopamine D3 and D5 receptor, respectively, were similar in subjects of different ages. The density of dopamine D3 receptor binding sites was slightly decreased in subjects of 30-39 years in comparison with younger individuals. A remarkable loss of dopamine D3 receptor was then found between 40 and 49 years of age in comparison with younger subjects. A further slight decrease was noticeable between 50 and 59 years of age. The number of [3H]7-OH-DPAT binding sites was then stabilized after 60 years of age. The density of dopamine D5 receptor binding sites did not show age-dependent changes. The above findings indicate the occurrence of a decline in the density of lymphocyte dopamine D3 but not D5 receptor between adult and mature subjects. The possibility that dopamine D3 receptor assay in peripheral blood lymphocytes may represent a tool for investigating dopamine receptor function in aging and age-related neurological disorders is discussed.

Adult↗

PubMed1996

Muscarinic thioligands with cyclopentane nucleus.

Some thio- and the benzoyl-derivatives of deoxamuscarine were synthesized and tested as muscarinic agonists using radioligand binding assays and functional tests. In comparison with deoxamuscarine, used as reference compound, no dimension/distance modification is tolerated for correct lipophilic pocket recognition. The substitution of the ammonium group with a sulphonium group significantly decreased muscarinic potency. The so-called 'muscarinic sub-site' accepts relatively bulky functions as long as it is bound to the cyclopentane carrier by an oxygen bridge. Esterification of this moiety increases the M2 subtype selectivity, while etherification heightens that of M3.

Animals↗

PubMed1996

Vascular and neuronal hypertensive brain damage: protective effect of treatment with nicardipine.

AIM: The brain is sensitive to hypertension, which causes a variety of vascular and neuronal cerebral changes. The present study was designed to assess the effect of long-term treatment with the Ca2+ channel blocker nicardipine on intracerebral (intraparenchymal) arteries in spontaneously hypertensive rats (SHR) by using microanatomical techniques associated with image analysis. The effects of hypertension and treatment with nicardipine on nerve cells and glial fibrillary acid protein (GFAP)-immunoreactive glial cells were also evaluated. EFFECTS OF NICARDIPINE ON BLOOD PRESSURE: In SHR a significant increase in systolic blood pressure in comparison with age-matched normotensive Wistar-Kyoto (WKY) rats was noticeable. Treatment with nicardipine significantly reduced systolic pressure in the SHR. The media: lumen ratio and the thickness of the tunica media were increased in medium (diameter between 150 and 50 microns and small (diameter < 50 microns intracerebral arteries. This phenomenon was accompanied by luminal narrowing. Treatment with nicardipine significantly reduced the thickness of the tunica media, the media: lumen ratio and increased the luminal area, primarily at the level of small pial arteries and of intracerebral arteries. EFFECTS OF NICARDIPINE IN THE BRAIN: In control SHR, the number of neurones in the frontal and occipital cortex was reduced in comparison with normotensive WKY rats. GFAP-immunoreactive astrocytes were increased in number (hyperplasia) and in size (hypertrophy), both in the frontal cortex and in the occipital cortex of control SHR. In the CA1, field of the hippocampus, the number of neurones and their size were decreased in SHR in comparison with normotensive WKY rats. Hyperplasia of GFAP-immunoreactive astrocytes of white matter and hypertrophy of those of grey matter was also noticeable. No important changes were found in other portions of the hippocampus. Treatment with nicardipine increased the number of neurones in the frontal cortex and in the occipital cortex of SHR and countered hyperplasia and hypertrophy of GFAP-immunoreactive astrocytes. Moreover, it increased the number of neurones in the CA1 field of the hippocampus and decreased the number and the size of astrocytes of the white matter and grey matter, respectively. CONCLUSIONS: These findings show that treatment of SHR with nicardipine significantly reduced systolic blood pressure and induced moderate vasodilation of both extracerebral and intracerebral arteries regulating cerebrovascular resistance. The compound also countered some microanatomical changes occurring in the hypertensive brain. The frontal and occipital (visual) cortex and the CA1 field of the hippocampus were the cerebral areas more sensitive to treatment with nicardipine. This suggests that nicardipine induces moderate cerebrovascular dilation and exerts neuroprotective effects on SHR neurones. The possible relevance of the neuroprotective actions of nicardipine in the hypertensive brain deserves to be evaluated in future studies.

Animals↗

PubMed1996

Organization and activities of the International Radio Medical Centre (CIRM).

The International Radio Medical Centre (CIRM) was founded in 1935, to provide free medical assistance by radio to ships with no doctor on board and others who cannot be reached by a doctor. In 1950 CIRM was established as a non-profit-making foundation and has benefited since 1957 from an annual contribution from the Italian government. The results achieved by the Centre over 61 years include medical assistance to 42,935 patients on board ships (as well as on small islands and aircraft), with 375,264 medical messages received and transmitted. CIRM is organized into a medical service, a telecommunications service and a studies section. The 24-h continuous medical service is provided by doctors at the CIRM headquarters. The doctor on duty gives instructions for managing the case. If necessary the medical service will coordinate the patient's hospitalization at the nearest port with suitable medical facilities or arrange the patient's transfer to another ship with a doctor on board, or an airlift. The telecommunications service receives requests for assistance, locates the ship or whoever made the request, passes the call to the doctor on duty, and relays the doctor's response to those requesting assistance. The studies section, established in 1957-58, researches occupational pathologies of sailors and contributes to their prevention. This provides a scientific basis for improving medical assistance to sailors at sea.

Emergencies↗

PubMed1995

Microanatomical and electrophysiological changes of the rat dentate gyrus caused by lesions of the nucleus basalis magnocellularis.

The effect of unilateral or bilateral lesions of the nucleus basalis magnocellularis (NBM) on the dentate gyrus of the hippocampus were assessed using microanatomical and electrophysiological techniques. NBM is the main cholinergic basal forebrain nucleus that supplies the fronto-parietal cortex. Lesions were induced using the neurotoxin ibotenic acid or a radio-frequency system and did not affect glutamic acid decarboxylase activity both in the frontal cortex and in the hippocampus. At 4 weeks after lesioning, a loss of choline acetyltransferase (ChAT) activity and of ChAT-immunoreactive fibres was observed in the frontal cortex but not in the hippocampus and no changes in the density of granule neurons of the dentate gyrus or in the hippocampal long-term potentiation (LTP) were noticeable. At 8 weeks after lesioning the loss of both ChAT activity and of ChAT-immunoreactive fibres persisted in the frontal cortex of NBM-lesioned rats. Moreover, at this time a significant decrease in the density of granule neurons in the dentate gyrus accompanied by a reduced probability of dentate LTP induction were observed in both ibotenic acid- and radio-frequency-lesioned rats. These findings have shown that although NBM does not send direct cholinergic projections to the hippocampus, lesions of this cholinergic nucleus are accompanied by delayed neurodegenerative changes involving the dentate gyrus. This suggests the occurrence of indirect connections between NBM and the hippocampus, the functional relevance of which should be explored.

Animals↗

PubMed1995

Localisation of dopamine D3 receptor in the rat cerebellar cortex: a light microscope autoradiographic study.

The pharmacological properties and the anatomical localisation of dopamine D3 receptor were assessed in the rat cerebellar cortex using radioligand binding techniques associated with light microscope autoradiography and 7-[3H]hydroxy-N,N-di-n-propyl-2-aminotetralin (7-[3H]OH-DPAT) as a ligand. 7-[3H]OH-DPAT was specifically bound to sections of rat cerebellar cortex with a dissociation constant (Kd) of 0.5 nM and a maximum density of binding sites (Bmax) of 97 +/- 4 fmol/mg tissue. The rank order of potency of competitors of 7-[3H]OH-DPAT binding and the observation that guanosine triphosphate did not affect radioligand binding suggest the labelling of a dopamine D3 receptor. 7-[3H]OH-DPAT binding sites are located mainly in the molecular layer and in lesser amounts in the Purkinje neuron layer, primarily within the cell body of Purkinje neurons. No specific accumulation of silver grains was observed in the granule neuron layer or in the white matter of the cerebellar cortex. The localisation of a putative dopamine D3 receptor within Purkinje neurons suggests that this site may have functional relevance in the cerebellar cortex.

Animals↗

PubMed1995

Muscarinic cholinergic receptors in dorsal root ganglia of chick embryo: a radioligand binding and immunocytochemical study.

The presence and micro-anatomical localization of muscarinic cholinergic receptors were assessed in dorsal root ganglia of chick embryo during development using radioligand binding and immunocytochemical techniques, respectively. The non-selective muscarinic cholinergic receptor radioligand [3H]quinuclidinyl benzilate was specifically bound to sections of chick dorsal root ganglia with a dissociation constant value (Kd) of 0.75 +/- 0.02 nM and a maximum density of binding sites (Bmax) of 7.2 +/- 0.5 fmol/mg tissue. [3H]Quinuclidinyl benzilate binding was partially sensitive to pirenzepine displacement. This suggests that muscarinic cholinergic receptors expressed by dorsal root ganglia of chick embryo at least in part belong to the M1 muscarinic receptor subtype. Immunocytochemical analysis confirmed the presence of muscarinic receptors in the ganglia. These findings suggest that neurons of dorsal root ganglia, which are known to express cholinergic markers such as choline acetyltransferase, acetylcholinesterase and high affinity choline uptake, are also cholinoceptive.

Animals↗

PubMed1995

Effect of long-term treatment with L-deprenyl on the age-dependent microanatomical changes in the rat hippocampus.

Chronic treatment with L-deprenyl increases both mean and maximum life span and improves cognitive functions in the aged rat. The present study was designed to evaluate whether long-term treatment with L-deprenyl at a dosage not inhibiting the monoamine oxidase-B (MAO-B) (1.25 mg/kg/day) or inhibiting the enzyme activity (5 mg/kg/day) had any effect on the age-dependent microanatomical changes in the rat hippocampus. The hippocampus was chosen in view of its key role in learning and memory functions. Treatment with L-deprenyl started at 19 months and lasted until the 24th month of age. Age-matched untreated rats were used as a control, whereas 11-month-old rats were used as an adult reference group. The number of nerve cell and glial fibrillary acidic protein-immunoreactive astrocyte profiles in the CA1 and CA3 fields of the hippocampus and in the dentate gyrus was decreased and increased, respectively in aged compared with adult rats. Treatment with 5 mg/kg/day, but not with 1.25 mg/kg/day L-deprenyl increased the number of neuronal profiles and decreased the number of astrocytes in the hippocampus of aged rats. The density of zinc stores in the associative intrahippocampal pathway of mossy fibres, which was decreased in aged animals, was increased after treatment with the two doses of L-deprenyl. Lipofuscin accumulation within the cytoplasm of pyramidal neurons of the hippocampus was reduced dose dependently by L-deprenyl treatment. These results suggest that long-term treatment with L-deprenyl is able to counter the expression of age-dependent microanatomical changes in the rat hippocampus. These effects seem only partially correlated with the MAO-B inhibitory activity of L-deprenyl.

Aging↗

PubMed1995

Effect of long-term treatment with the dihydropyridine-type calcium channel blocker darodipine (PY 108-068) on the cerebral capillary network in aged rats.

The effects of treatment with the dihydropyridine Ca+2 antagonist darodipine (PY 108-068) on age-related changes in the cerebral capillary network was studied using alkaline phosphatase histochemistry with quantitative image analysis. The investigation was performed on male Wistar rats of 12 months (adult reference group) and 27 months. The 27-month-old rats consisted of two groups, the first of control untreated animals and the second of rats receiving an oral dose of 5 mg/kg/day of darodipine from the 21st to the 27th month. The cerebral areas examined included the frontal cortex, the occipital cortex, Ammon's horn of the hippocampus, and the dentate gyrus. The number and the average length of alkaline phosphatase-positive capillaries were decreased in old rats, when compared with adult rats. The intercapillary distance, which is considered as a sensitive parameter for capillary density was increased in aged rats in comparison to adult rats. The capillary diameter was increased slightly or unchanged in old rats. The Ammon's horn and the frontal cortex were the cerebral areas most affected by age-dependent changes of the capillary network. Treatment with darodipine increased the number and the average length of alkaline phosphatase-reactive capillaries and reduced the intercapillary distance and the diameter of cerebral capillaries in old rats. The pericapillary microenvironment of the Ammon's horn was the most sensitive to treatment with darodipine. The above results showed that treatment with darodipine is capable of counteracting some microvascular changes occurring in the brain of aged rats. This suggests that the blockade of dihydropyridine-type Ca2+ channels has a positive effect on the brain microvascular system and may counteract the impairment of pericapillary microenvironment occurring with aging.

Aging↗

PubMed1995

Effect of treatment with the dihydropyridine-type calcium antagonist darodipine (PY 108-068) on the expression of calbindin D-28K immunoreactivity in the cerebellar cortex of aged rats.

The influence of long term treatment with the dihydropyridine-type Ca2+ antagonist darodipine (PY 108-068) on age-dependent changes in calbindin D-28K immunoreactivity in the cerebellar cortex of male Wistar rats was assessed. In 12-month-old rats used as an adult reference group, specific calbindin D-28K immunoreactivity was found within the cytoplasm of Purkinje neurons and their dendritic processes. The number of Purkinje neurons displaying calbindin D-28K immunoreactivity was decreased in the cerebellar cortex of aged in comparison with adult rats. The pattern of calbindin D-28K immunoreactivity was similar in the cerebellar cortex of 24-month-old rats (aged), although a significant decrease in the intensity of immunoreactivity was noticeable. Treatment of aged rats with darodipine for 6 months increased the percentage of immunoreactive Purkinje neurons and the intensity of calbindin D-28K immunoreactivity in the cytoplasm of Purkinje neurons. Calbindin D-28K is a Ca2+ binding protein probably involved in the modulation of Ca2+ homeostasis. The observation of a positive effect of darodipine treatment on calbindin D-28K immunoreactivity in the cerebellar cortex suggests that manipulation of dihydropyridine-type Ca2+ channels may contribute to counter age-dependent changes of Ca2+ homeostasis.

Aging↗

PubMed1995

Identification of age-related changes of dopamine D1-like receptors in the rat cerebellar cortex.

The present study was designed to characterize the pharmacological profile of dopamine D1-like receptors in the rat cerebellar cortex and to assess if these receptor sites undergo age-related changes. Cerebella of young (3 months), adult (12 months), and old (27 months) male Wistar rats were examined by using radioligand binding techniques and light microscope autoradiography. The non-selective dopamine D1-like radioligand [3H]SCH 23390 was specifically bound to sections of rat cerebellum. The findings that dopamine displaced [3H]SCH 23390 binding in the submicromolar range suggest that labelling of a dopamine D5 (or D1B) receptor subtype. The affinity of [3H]SCH 23390 for dopamine D1-like receptors was similar in the cerebellar cortex of the three animal groups investigated, whereas radioligand binding techniques revealed a gradual age-related reduction of the density of binding sites. Light microscope autoradiography showed the localization of [3H]SCH 23390 binding sites primarily in the molecular layer and to a lesser extent in the Purkinje neuron layer of the cerebellar cortex. Aging was accompanied by a loss of [3H]SCH 23390 binding sites affecting mainly the molecular layer. The age-dependent loss of dopamine D1-like receptors is more pronounced if detected with radioligand binding techniques than with light microscope autoradiography. This suggests that the decrease of dopamine D1-like receptors observed in aging rat cerebellar cortex may depend in part on changes in the receptor expression and in part on cortico-cerebellar structural changes.

Age Factors↗

PubMed1995

Dopamine D1-like receptors in the thymus of aged rats: a radioligand binding and autoradiographic study.

Age-dependent changes in the density and pattern of dopamine D1-like receptors were studied in the thymus of young (3 months), adult (12 months) and aged (24 months) male Wistar rats using combined radioligand binding and autoradiographic techniques. [3H]SCH 23390, which was used as a ligand, was specifically bound to sections of the thymus in a manner consistent with the labelling of dopamine D5 receptor. The dissociation constant value was similar in the thymus of the three animal groups examined. The maximal density of binding sites, evaluated with conventional radioligand binding techniques, was significantly reduced in the thymus of adult in comparison with young rats and further reduced in aged animals. Silver grains which correspond to [3H]SCH 23390 binding sites were revealed by light microscope autoradiography primarily in the cortex of the thymus and in lesser amounts within thymic corpuscles. A progressive decrease in the density of silver grains more pronounced in the cortex than in thymic corpuscles was observed in the thymus of adult and old in comparison with young rats. The loss of silver grains revealed with autoradiography is more moderate than the decrease in the density of binding sites shown by radioligand binding. Silver grains developed per single cells (probably lymphocytes) of the thymic cortex were reduced between young and adult rats and further decreased in old rats. The above findings suggest that the age-related decline in the density of dopamine D5 receptor assayed in the thymus is due in part to the reduced thymic mass with aging.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1995

Radioligand binding characterization of putative dopamine D3 receptor in human peripheral blood lymphocytes with [3H]7-OH-DPAT.

The presence and the pharmacological profile of dopamine D3 receptor have been investigated in human peripheral blood lymphocytes using radioligand binding techniques and the selective dopamine D3 receptor agonist [3H]7-hydroxy-N,N-di-n-pro-pyl-2-aminotetralin ([3H]7-OH-DPAT) as a ligand. [3H]7-OH-DPAT binding to human peripheral blood lymphocytes was time-, temperature-, and concentration-dependent and of high affinity with a dissociation constant value (Kd) of 0.27 +/- 0.05 nM and a maximum binding density (Bmax) of 14.7 +/- 0.06 fmol/2 x 10(6) cells. Binding was also reversible. The rank order of potency of displacers of [3H]7-OH-DPAT binding to human peripheral blood lymphocytes resembled that found for dopamine D3 receptor in rat brain homogenates or in rat or human cell lines. Our findings, which are consistent with those of other authors performed with molecular biology techniques, suggest that human peripheral blood lymphocytes express dopamine D3 receptor. In the brain, dopamine D3 receptor probably mediates the anti-psychotic effect of neuroleptics. The availability of a rapid and reproducible technique for its assay may contribute to evaluate its status in brain disorders characterized by impaired dopaminergic neurotransmission.

Humans↗

PubMed1995

Age-related changes in brain microanatomy: sensitivity to treatment with the dihydropyridine calcium channel blocker darodipine (PY 108-068).

The influence of aging and of treatment with the dihydropyridine Ca2+ antagonist darodipine (PY 108-068) on the age-related microanatomical changes of rat brain were studied in male Wistar rats treated from the 18th to the 24th month of age with an oral dose of 5 mg/kg/day of darodipine. Twelve-month-old untreated rats were used as an adult reference group. A decreased number of nerve cells and of alkaline phosphatase-positive capillaries and an increased lipofuscin deposition were observed in the frontal and occipital cortex, in the hippocampus, and in the cerebellar cortex of rats of 24 months in comparison with 12-month-old animals. The number of nerve cells was higher in the occipital cortex and in the hippocampus, but not in the frontal cortex and in the cerebellar cortex, of darodipine-treated rats in comparison with age-matched untreated animals. Lipofuscin deposition is reduced in all the brain areas investigated. The density of alkaline phosphatase-reactive capillaries is also increased in the frontal and occipital cortex and in the hippocampus of aged rats treated with darodipine. The above results suggest that treatment with darodipine is able to counter some microanatomical changes occurring in the brain of aged rats and involving not only microvascular parameters. The occipital (visual) cortex and the hippocampus were the cerebral areas more sensitive to treatment with darodipine. The possible relevance of these findings is discussed.

Aging↗

PubMed1995

Pharmacological characterization and autoradiographic localization of dihydropyridine-type calcium channels in the kidney of spontaneously hypertensive rats.

1. The pharmacological profile and the microanatomical localization of Ca2+ channels of the L-type were analysed in sections of the kidney of Wistar-Kyoto (WKY) rats and of spontaneously hypertensive rats (SHR) of different ages. 2. [3H]-Nicardipine was used as a ligand. It was bound to sections of rat kidney in a manner consistent with the labelling of Ca2+ channels of the L-type. The density of [3H]-nicardipine binding sites was similar in WKY rats of different ages and in SHR of 2 and 4 months, but was significantly increased in SHR of 6 months. 3. Light microscope autoradiography revealed the highest density of binding sites in the tubular portion of the nephron and to a lesser extent within smooth muscle of renal arteries and renal corpuscles. In SHR of 4 and 6 months the density of [3H]-nicardipine binding sites was increased within the epithelium of proximal tubules and of the loop of Henle and decreased in renal corpuscles in comparison with WKY rats or 2 month old SHR. 4. These results show that the density of Ca2+ channels of the L-type increases with the worsening of hypertension in SHR. The observation of a different sensitivity to hypertension of Ca2+ channels located in the various portions of the nephron indicates the usefulness of light microscope autoradiography for assessing hypertension-related changes of Ca2+ channels in the kidney.

Animals↗

PubMed1995

Protective effect of nicardipine treatment on cerebrovascular microanatomical changes in spontaneously hypertensive rats.

1. The effect of long-term treatment with the dihydropyridine Ca2+ antagonist, nicardipine, on the morphology of different sized pial arteries was assessed in spontaneously hypertensive rats (SHR) using histological techniques associated with image analysis. 2. In control 20 week old SHR blood pressure values, the thickness of the tunica media, the media-to-lumen ratio and connective tissue content were significantly increased in comparison with reference normotensive Wistar-Kyoto (WKY) rats. 3. Treatment for 8 weeks with a daily dose of 3 mg/kg of nicardipine decreased blood pressure values in SHR and significantly reduced the area occupied by the tunica media and the media-to-lumen ratio. This effect was observed primarily in small sized pial arteries and to a lesser extent in medium sized pial arteries. Nicardipine administration was without effect on connective tissue content in the wall of cerebral arteries. 4. These results indicate that treatment with nicardipine reduces blood pressure elevation in SHR and exerts a protective effect on arteries controlling cerebrovascular resistance. The activity of the compound primarily on small sized pial arteries may protect the brain from generalized vasodilation which could cause cerebral hypoperfusion.

Animals↗

PubMed1995

Influence of long-term treatment with the dihydropyridine-type calcium antagonist nicardipine on renal microanatomical changes in spontaneously hypertensive rats.

1. The influence of hypertension and treatment with the dihydropyridine-type Ca2+ antagonist, nicardipine, on the structure of the kidney was assessed in spontaneously hypertensive rats (SHR) of 12 weeks of age. Treatment went for 8 weeks with a daily oral dose of 1 mg/kg of nicardipine. 2. Control SHR exhibited hypertension and microanatomical vascular and glomerular changes. Vascular changes consisted of a thickening of the tunica media and decreased luminal area of medium- and small-sized intrarenal artery branches. Glomerular changes included glomerulosclerosis and atrophy of varying degrees. 3. Administration of nicardipine significantly reduced blood pressure. The drug also decreased the thickening of tunica media and luminal narrowing of renal artery branches as well as the degree of glomerular injury in SHR. 4. These data indicate that nicardipine treatment is able to control elevated blood pressure in SHR, and to counter hypertension-dependent microanatomical impairment of the kidney. This suggests that the compound exerts a protective effect on hypertensive kidney.

Animals↗

PubMed1995

Localisation of dopamine D1-like and D2-like receptors in the pulmonary vasculature.

The pharmacological profile and the anatomical localisation of dopamine receptor subtypes were investigated in the rabbit pulmonary vascular bed using combined radioligand binding and light microscope autoradiography techniques. Dopamine D1-like receptor sites, which probably belong to the dopamine D1 receptor subtype, were characterized in sections of lung using [3H]-SCH 23390 as a ligand. These sites were located within the tunica intima and the tunica media of large sized intrapulmonary artery branches and in the tunica media of medium sized intrapulmonary artery branches. Dopamine D2-like receptor sites, which probably belong to the dopamine D2 receptor subtype, were characterized using [3H]-spiroperidol as a ligand. These sites were located within the tunica adventitia of both extra- and intrapulmonary artery branches. Dopamine D2-like receptor sites were also found in the tunica adventitia of the human pulmonary artery, but not of the rat pulmonary artery. The different anatomical localization of dopamine D1 and D2 receptor subtypes in the pulmonary vasculature suggests that these sites are involved in the modulation of pulmonary vascular tone by interacting with different receptors unevenly distributed throughout the pulmonary vascular bed.

Animals↗