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  • 1
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Exposure of synaptosomes isolated from the electric organ of Torpedo marmorata to conditions that promote the release of acetylcholine does not cause the co-release of a vesicle specific proteoglycan. Proteoglycan within synaptosomes is quite stable during various incubation conditions as measured by immune dot blotting. Isolated vesicles from Torpedo also retain their proteoglycan immunoreactivity when exposed to a variety of incubation conditions. Lysis of vesicles in H2O, treatment with pH 11.5 buffer, or exposure to high ionic strength (2 M KCl) results in the loss of acetylcholine or ATP while the proteoglycan is retained by vesicle membranes. Only treatment with Nonidet P-40 releases proteoglycan from vesicles or synaptosomes and free proteoglycan immunoreactivity is then susceptible to degradation by trypsin or heparinase. These results suggest that the proteoglycan is an integral component of vesicle membranes and is at least in the synaptosomal preparation not subject to extensive co-release with acetylcholine or ATP.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2072
    Keywords: d-Amphetamine ; CNS Stimulants ; Discrimination ; State-Dependent Learning ; Hallucinogenic Drugs ; δ 9-THC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Male albino rats were trained and tested on a two-lever discrimination task based upon the presence or absence of d-amphetamine (1.0 mg/kg). This compound was found to produce strong discriminative cues (i.e., 90% correct choice behavior). A dose-effect function was then ascertained and the discriminative ED50 (following training with 1.0 mg/kg) was found to be 0.23 mg/kg d-amphetamine. In order to determine the effective duration of d-amphetamine action, the interval between injection and testing was varied; it was found that the discriminative effects of the drug began to dissipate between 60 and 90 min post-injection. In an attempt to compare the discriminative cues of other drugs with those of d-amphetamine, injections of LSD (0.04 and 0.08 mg/kg), psilocybin (0.50 and 1.0 mg/kg), THC (0.50 and 1.0 mg/kg), mescaline (5.0 and 10.0 mg/kg), and caffeine (6.0 and 20.0 mg/kg) were given during extinction. In all cases, the rats responded predominantly on the saline-related lever. Only methamphetamine (1.0 mg/kg) produced d-amphetamine-like responding. Finally, alpha-methyl-para-tyrosine (AMPT), a compound which depletes brain catecholamines (CA), was found to disrupt the d-amphetamine-saline discrimination.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2072
    Keywords: LSD ; Discriminable Properties of Drugs ; Serotonin Receptors ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats were initially trained to discriminate LSD from saline in two-lever operant chambers by reinforcing responses only on one lever following intraperitoneal injections of 80 Μg/ kg of LSD and only on the other lever following saline injections. Choice responding during extinction periods (no water reinforcement for either response) indicated a high level of discriminability (95% correct) following either LSD or saline. A dose-response curve for LSD, obtained by tests for lever choice after injections of 10, 20, 30, 40, 50, and 60 Μg/kg, indicated that 10 Μg/kg produced only 30% responding on the LSD lever. This percentage was increased (to 83%) by reinforcing responding on the LSD lever following injections of 10 Μg/kg. Subsequent tests indicated that doses of 5.0 and 2.5 Μg/kg produced a majority of responses on the LSD lever. Since at these low doses LSD has few measurable biochemical or behavioral effects, we hypothesize that the discriminable cue of LSD is related to direct stimulation of central serotonergic receptors.
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  • 4
    ISSN: 1432-0878
    Keywords: Neuronal markers ; Neuropeptides ; Immunohistochemistry ; Heart innervation ; Atrial natriuretic peptide (ANP) ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation and myocardial cells of the human atrial appendage were investigated by means of immunocytochemical and ultrastructural techniques using both tissue sections and whole mount preparations. A dense innervation of the myocardium, blood vessels and endocardium was revealed with antisera to general neuronal (protein gene product 9.5 and synaptophysin) and Schwann cell markers (S-100). The majority of nerve fibres possessed neuropeptide Y immunoreactivity and were found associated with myocardial cells, around small arteries and arterioles at the adventitial-medial border and forming a plexus in the endocardium. Subpopulations of nerve fibres displayed immunoreactivity for vasoactive intestinal polypeptide, somatostatin, substance P and calcitonin gene-related peptide. In whole-mount preparations of endocardium, substance P and calcitonin gene-related peptide immunoreactivities were found to coexist in the same varicose nerve terminals. Ultrastructural studies revealed the presence of numerous varicose terminals associated with myocardial, vascular smooth muscle and endothelial cells. Neuropeptide Y immunoreactivity was localised to large electron-dense secretory vesicles in nerve terminals which also contained numerous small vesicles. Atrial natriuretic peptide immunoreactivity occurred exclusively in myocardial cells where it was localised to large secretory vesicles. The human atrial appendage comprises a neuroendocrine complex of peptidecontaining nerves and myocardial cells producing ANP.
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  • 5
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The cutaneous nerves of rat, cat, guinea pig, pig, and man were studied by immunocytochemistry to compare the staining potency of general neural markers and to investigate the density of nerves containing peptides. Antiserum to protein gene product 9.5 (PGP 9.5) stained more nerves than antisera to neurofilaments, neuronspecific enolase (NSE), and synaptophysin or histochemistry for acetylcholinesterase (AChE). Peptidergic axons showed species variation in density of distribution and were most abundant in pig and fewest in man. However, the specific peptides in nerves innervating the various structures were consistent between species. Nerve fibers immunoreactive for calcitonin gene-related peptide (CGRP) and/or vasoactive intestinal polypeptide (VIP) predominated in all the species; those immunoreactive to tachykinins (substance P and neurokinin A [NKA]) and neuropeptide tyrosine (NPY) were less abundant. Neonatal capsaicin, at the doses employed in this study, destroyed approximately 70% of CGRP- and tachykinin-immunoreactive sensory axons; whereas 6-hydroxydopamine (6-OHDA) at the doses employed resulted in a complete loss of NPY and tyrosine hydroxylase (TH) immunoreactivity without affecting VIP, CGRP, and tachykinins.Thus, this study confirms that antiserum to PGP 9.5 is the most suitable and practical marker for the demonstration of cutaneous nerves. Species differences exist in the density of peptidergic innervation, but apparently not for specific peptides. Not all sensory axons immunoreactive for CGRP and substance P/NKA are capsaicin-sensitive. However, all sympathetic TH- and NPY- immunoreactive axons are totally responsive to 6-OHDA; but no change was seen in VIP-immunoreactive axons, suggesting some demarcation of cutaneous adrenergic and cholinergic sympathetic fibers.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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