1
|
Wang Y, Fu M, Yang Y, Zhang J, Zhang Z, Xiao J, Zhou Y, Yan F. Modification of PEG reduces the immunogenicity of biosynthetic gas vesicles. Front Bioeng Biotechnol 2023; 11:1128268. [PMID: 36949883 PMCID: PMC10025544 DOI: 10.3389/fbioe.2023.1128268] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 02/22/2023] [Indexed: 03/08/2023] Open
Abstract
Nanobubbles have received great attention in ultrasound molecular imaging due to their capability to pass through the vasculature and reach extravascular tissues. Recently, gas vesicles (GVs) from archaea have been reported as acoustic contrast agents, showing great potential for ultrasound molecular imaging. However, the immunogenicity and biosafety of GVs has not yet been investigated. In this study, we examined the immune responses and biosafety of biosynthetic GVs and polyethylene glycol (PEG)-modified GVs (PEG-GVs) in vivo and in vitro. Our findings suggest that the plain GVs showed significantly stronger immunogenic response than PEG-GVs. Less macrophage clearance rate of the RES and longer circulation time were also found for PEG-GVs, thereby producing the better contrast imaging effect in vivo. Thus, our study demonstrated the PEG modification of biosynthetic GVs from Halobacterium NRC-1 is helpful for the future application of GVs in molecular imaging and treatment.
Collapse
Affiliation(s)
- Yuanyuan Wang
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- NHC Key Laboratory of Family Planning and Healthy, Hebei Key Laboratory of Reproductive Medicine, Hebei Reproductive Hospital, Hebei Institute of reproductive health science and technology, Shijiazhuang, China
| | - Meijun Fu
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yaozhang Yang
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Jinghan Zhang
- Department of Ultrasonography, Capital Medical University Affiliated Beijing Anzhen Hospoital, Beijing, China
| | - Zhaomeng Zhang
- NHC Key Laboratory of Family Planning and Healthy, Hebei Key Laboratory of Reproductive Medicine, Hebei Reproductive Hospital, Hebei Institute of reproductive health science and technology, Shijiazhuang, China
| | - Jingling Xiao
- NHC Key Laboratory of Family Planning and Healthy, Hebei Key Laboratory of Reproductive Medicine, Hebei Reproductive Hospital, Hebei Institute of reproductive health science and technology, Shijiazhuang, China
| | - Yingjie Zhou
- NHC Key Laboratory of Family Planning and Healthy, Hebei Key Laboratory of Reproductive Medicine, Hebei Reproductive Hospital, Hebei Institute of reproductive health science and technology, Shijiazhuang, China
- *Correspondence: Fei Yan, ; Yingjie Zhou,
| | - Fei Yan
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Fei Yan, ; Yingjie Zhou,
| |
Collapse
|
2
|
Bowery NG, Doble A, Hill DR, Hudson AL, Shaw J, Turnbull MJ. A Novel Gaba Receptor on Central Neurones. Scott Med J 2016. [DOI: 10.1177/003693308002500436] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The features of γ-aminobutyric acid (GABA) as an inhibitory neurotransmitter are described, together with those of its receptor as defined by both iontophoretic and radiolabelled ligand binding techniques. Evidence is presented supporting the existence of a second GABA receptor at both peripheral nerve endings and within the CNS. At the classical receptor, GABA can produce a depolarisation of the ganglion cell body or mediate hyperpolarisation within the CNS by increasing membrane conductance to chloride ions. At this second receptor GABA acts in a bicuculline-insensitive manner to reduce neurotransmitter outflow. Many GABA analogues active at the classical receptor are inactive at the second receptor but by contrast baclofen which is inactive at the classical receptor is a potent agonist at the novel site.
Collapse
Affiliation(s)
- N. G. Bowery
- Department of Pharmacology, St. Thomas's Hospital Medical School, London SE1 7EH and Biology Department, ICI Pharmaceuticals, Mereside, Alderley Park, Macclesfield, Cheshire SK10 4TG
| | - A. Doble
- Department of Pharmacology, St. Thomas's Hospital Medical School, London SE1 7EH and Biology Department, ICI Pharmaceuticals, Mereside, Alderley Park, Macclesfield, Cheshire SK10 4TG
| | - D. R. Hill
- Department of Pharmacology, St. Thomas's Hospital Medical School, London SE1 7EH and Biology Department, ICI Pharmaceuticals, Mereside, Alderley Park, Macclesfield, Cheshire SK10 4TG
| | - A. L. Hudson
- Department of Pharmacology, St. Thomas's Hospital Medical School, London SE1 7EH and Biology Department, ICI Pharmaceuticals, Mereside, Alderley Park, Macclesfield, Cheshire SK10 4TG
| | - J. Shaw
- Department of Pharmacology, St. Thomas's Hospital Medical School, London SE1 7EH and Biology Department, ICI Pharmaceuticals, Mereside, Alderley Park, Macclesfield, Cheshire SK10 4TG
| | - M. J. Turnbull
- Department of Pharmacology, St. Thomas's Hospital Medical School, London SE1 7EH and Biology Department, ICI Pharmaceuticals, Mereside, Alderley Park, Macclesfield, Cheshire SK10 4TG
| |
Collapse
|
3
|
|
4
|
Krishna PR, Reddy PS. “Diversity Oriented Synthesis” of Functionalized Chiral Tetrahydropyridines: Potential GABA Receptor Agonists and Azasugars from Natural Amino Acids via a Sequential Baylis−Hillman Reaction and RCM Protocol. ACTA ACUST UNITED AC 2008; 10:426-35. [DOI: 10.1021/cc700171p] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Palakodety Radha Krishna
- D-206/B, Discovery Laboratory, Organic Chemistry Division III, Indian Institute of Chemical Technology, Hyderabad 500 007, India
| | - P. Srinivas Reddy
- D-206/B, Discovery Laboratory, Organic Chemistry Division III, Indian Institute of Chemical Technology, Hyderabad 500 007, India
| |
Collapse
|
5
|
Seidel J, Niggemann B, Punzel M, Fischer J, Zänker KS, Dittmar T. The neurotransmitter GABA is a potent inhibitor of the stromal cell-derived factor-1alpha induced migration of adult CD133+ hematopoietic stem and progenitor cells. Stem Cells Dev 2008; 16:827-36. [PMID: 17999603 DOI: 10.1089/scd.2007.0004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The ability of hematopoietic stem and progenitor cells (HSPCs) to migrate is a prerequisite for bone marrow homing and tissue regeneration processes. Induction of HSPC migration is chiefly directed by stromal cell-derived factor-1alpha (SDF-1alpha). Considerably less is known about factors that terminate HSPC migration. Adult CD133(+) HSPCs were isolated from mobilized peripheral blood by immunomagnetic separation. Cell migration was assessed using the three-dimensional collagen matrix migration assay, which allows detailed migration analysis on a cell population and single-cell level. The SDF-1alpha-induced locomotory activity of CD133(+) cells was efficiently blocked by the neurotransmitter gamma-aminobutyric acid (GABA). GABA signaling was effected via the GABA(B)-receptor. This was verified by flow cytometry and cell migration studies using the specific GABA(A)-receptor and GABA(B)-receptor agonists isoguvacine and baclofen, respectively. Baclofen blocked SDF-1alpha-induced migration of CD133(+) cells. Flow cytometry-based calcium measurements revealed that GABA inhibits the SDF-1alpha-induced migration of CD133(+) cells by blocking the SDF-1alpha-induced calcium influx. Similar results were obtained with the specific calcium-release-activated calcium (CRAC) channel inhibitor BTP-2, which both blocked the SDF-1alpha-induced calcium influx and migration of CD133(+) cells. These results suggest that GABA(B)-receptor signaling modulates the activity of CRAC channels, whereby the mechanism in detail remains unclear. In summary, the neurotransmitter GABA is a potent blocker of the SDF-1alpha-induced migration of CD133(+) HSPCs from mobilized peripheral blood.
Collapse
Affiliation(s)
- Jeanette Seidel
- Institute of Immunology, Witten/Herdecke University, 58448 Witten, Germany
| | | | | | | | | | | |
Collapse
|
6
|
Ulloor J, Mavanji V, Saha S, Siwek DF, Datta S. Spontaneous REM Sleep Is Modulated By the Activation of the Pedunculopontine Tegmental GABAB Receptors in the Freely Moving Rat. J Neurophysiol 2004; 91:1822-31. [PMID: 14702336 DOI: 10.1152/jn.01104.2003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Considerable evidence suggests that the neurotransmitter γ-aminobutyric acid (GABA)-ergic system and pedunculopontine tegmentum (PPT) in the brain stem are critically involved in the regulation of rapid-eye-movement (REM) sleep. GABA and its various receptors are normally present in the PPT cholinergic cell compartment. The aim of this study was to identify the role of GABA and its receptors in the regulation of REM sleep. To achieve this aim, specific receptors were activated differentially by local microinjection of selective GABA receptor agonists into the PPT while quantifying its effects on REM sleep in freely moving chronically instrumented rats ( n = 21). The results demonstrated that when GABAB receptors were activated by local microinjection of a GABAB receptor selective agonist, baclofen, spontaneous REM sleep was suppressed in a dose-dependent manner. The optimum dose for REM sleep reduction was 1.5 nmol. In contrast, when GABAA and GABAC receptors were activated by microinjecting their receptor selective agonists, isoguvacine (ISGV) and cis-4-aminocrotonic acid (CACA), respectively, the total percentages of REM sleep did not change compared with the control values. In another eight freely moving rats, effects of baclofen application was tested on firing rates of REM-on cells ( n = 12). Of those 12 neurons, 11 stopped firing immediately after application of baclofen [latency: 50 ± 14 s (SD)] and remained almost silent for 130 ± 12 min. Findings of the present study provide direct evidence that the PPT GABAB receptors and REM-on cells are involved in the regulation of REM sleep.
Collapse
Affiliation(s)
- Jagadish Ulloor
- Sleep Research Laboratory, Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | | | | | | | | |
Collapse
|
7
|
Ault B, Hildebrand LM. GABAA receptor-mediated excitation of nociceptive afferents in the rat isolated spinal cord-tail preparation. Neuropharmacology 1994; 33:109-14. [PMID: 8183434 DOI: 10.1016/0028-3908(94)90104-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Algogens such as capsaicin, bradykinin, acetylcholine, 5-hydroxytryptamine and potassium ions applied to exposed tail skin of the rat isolated spinal cord-tail preparation evoke a ventral root response consisting of depolarization and spiking activity. L-glutamate and kainate also evoke similar reflexes. All these compounds evoke depolarization of afferent axons or dorsal root ganglion cells. Since GABA depolarizes unmyelinated afferent fibers, the ability of GABA receptor agonists to activate cutaneous nociceptive afferents has been examined. GABA superfused over exposed tail skin evoked a ventral root reflex essentially identical to that produced by capsaicin (3 microM). The EC50 was 27 microM. Muscimol, 3-aminopropane sulphonate, isoguvacine and beta-alanine had effects comparable to GABA, with EC50 values of 9.6, 26, 56 and 870 microM respectively. Baclofen (100 microM) or glycine (10 mM) had no effect. Bicuculline applied to the tail competitively antagonized GABA (Schild slope = -1.03) with a pA2 of 5.8. Spinal application of 1 microM morphine blocked the actions of GABA and capsaicin. These data indicate that GABAA receptors can depolarize and excite nociceptive afferents. GABA could be involved in nociception by contributing to firing of C-fibres, or by analogy to presynaptic inhibition in the spinal cord, may act to decrease neuropeptide transmitter release in cutaneous tissue.
Collapse
Affiliation(s)
- B Ault
- Department of Neurosciences, Sterling Winthrop Pharmaceuticals Research Division, Collegeville, PA 19426-0900
| | | |
Collapse
|
8
|
Garant D, Sperber E, Moshé S. The density of GABAB binding sites in the substantia nigra is greater in rat pups than in adults. Eur J Pharmacol 1992; 214:75-8. [PMID: 1316282 DOI: 10.1016/0014-2999(92)90098-o] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Baclofen-displaced [3H]GABA (gamma-aminobutyric acid) binding to GABAB sites was assayed in brain regions obtained from adult and 14- to 17-day-old rats. The substantia nigra of rat pups exhibited a 3- to 5-fold higher density (Bmax) of GABAB binding sites than the nigra of adult rats. In contrast, the density of GABAB sites was lower in hippocampal and cerebellar tissue from pups, both approximately two-thirds the density in corresponding adult structures. This anatomically selective overproduction of GABAB receptors in immature substantia nigra is consistent with the increased anticonvulsant efficacy of the GABAB agonist baclofen observed in rat pups.
Collapse
Affiliation(s)
- D Garant
- Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461
| | | | | |
Collapse
|
9
|
Newberry NR, Gilbert MJ. Pertussis toxin sensitivity of drug-induced potentials on the rat superior cervical ganglion. Eur J Pharmacol 1989; 163:245-52. [PMID: 2721573 DOI: 10.1016/0014-2999(89)90193-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have investigated the action of pertussis toxin on a range of receptor-mediated responses of the rat superior cervical ganglion in vitro. The ganglia were treated with pertussis toxin for 24 h at 37 degrees C using an in vitro method. Appropriate controls were also carried out. Pertussis toxin (1 microgram/ml) reduced ganglionic hyperpolarisations mediated by adenosine, alpha 2, 5-HT1A, M2 and GABAB receptors. The GABAB-mediated hyperpolarisation of this preparation, evoked by baclofen and GABA in a bicuculline-resistant manner, has not previously been reported. Pertussis toxin did not reduce ganglionic depolarisations evoked by potassium chloride and 5-HT3, GABAA and nicotinic receptors. Depolarisations to muscarine and noradrenaline, probably mediated by M1 and beta-receptors, also appeared to be resistant to pertussis toxin. The similar sensitivity of the various ganglionic hyperpolarisations to pertussis toxin indicates that they may all be mediated by similar G-proteins.
Collapse
Affiliation(s)
- N R Newberry
- Merck Sharp & Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex, U.K
| | | |
Collapse
|
10
|
Wolff JR, Joó F, Kása P, Storm-Mathiesen J, Toldi J, Balcar VJ. Presence of neurons with GABA-like immunoreactivity in the superior cervical ganglion of the rat. Neurosci Lett 1986; 71:157-62. [PMID: 3024073 DOI: 10.1016/0304-3940(86)90551-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Using antibodies raised against gamma-aminobutyric acid (GABA)-glutaraldehyde complexes, we have found neurons with GABA-like immunoreactivity in the superior cervical ganglion of adult rats. The processes of these neurons formed pericellular networks around the principal ganglion cells. Electron microscopy revealed that the immunoreactive dendrites were innervated by non-reactive axon terminals which formed asymmetrical synapses and probably originated from the preganglionic nerve. Axons with GABA-like immunoreactivity, especially axonal varicosities filled with synaptic vesicles, were found in direct apposition to principal ganglion cells. The GABA-positive axons and axon varicosities persisted in experimentally decentralized (deafferented) ganglia, suggesting that the perikarya of the immunoreactive neurons were intrinsic to the superior cervical ganglion. Taken together with data on inhibitory effects of GABA in sympathetic ganglia, these findings suggest that the superior cervical ganglion of rats contains a subpopulation of inhibitory interneurons which is GABAergic. This would indicate that GABAergic neurons do not only occur in the central but also in the peripheral nervous system.
Collapse
|
11
|
Evans RH. Pharmacology of amino acid receptors on vertebrate primary afferent nerve fibres. GENERAL PHARMACOLOGY 1986; 17:5-11. [PMID: 2868969 DOI: 10.1016/0306-3623(86)90003-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Structure-activity of primary afferent depolarising action (PAD) mediated by gamma-aminobutyrate (GABA) analogues suggests a difference between subsynaptic receptors located at fibre terminations within the dorsal horn and axonal receptors which are distributed throughout non-synaptic regions. The interaction of the bicuculline-sensitive GABA receptor (GABA A) ionophore complex with barbiturates and benzodiazepines suggests that at least three binding sites are required to explain the independent GABA-mimetic, GABA-potentiating and picrotoxin-reversing effects of such agents. Difficulties with explanation of the depressant effects of baclofen on spinal transmission, in terms of the bicuculline-resistant GABA (GABA B) receptor hypothesis, are mentioned. Glutamate-induced PAD of low threshold afferents is mediated indirectly through release of potassium. However, such terminals possess receptors (possibly autoreceptors for L-glutamate), activated by (+)2-amino-4-phosphonobutyrate, which cause depression of transmitter release. Primary afferent C-fibres possess receptors which are selectively activated by kainate and which mediate picrotoxin-resistant PAD. Such receptors may be involved in the presynaptic conditioning of C-fibre transmitter release. The peripheral terminals of vestibular primary afferents, in amphibia, possess excitatory amino acid receptors which are probably activated by the transmitter released from hair cells.
Collapse
|
12
|
Abstract
GTP and GDP decreased the saturable binding of [3H]baclofen or [3H]gamma-aminobutyric acid ( [3H]GABA) to GABAB but not GABAA receptors whereas GMP displayed negligible activity. This effect was specific to guanyl nucleotides and was not mimicked by high concentrations of ATP. The inhibition of ligand binding was the result of a diminished receptor affinity with no change in receptor number. The use of a complete physiological saline solution rather than Tris buffer plus Ca2+ or Mg2+ increased the potency of GTP at the GABAB receptor. The results are discussed in relation to the effects of GABA and GTP on adenylate cyclase activity in the brain.
Collapse
|
13
|
|
14
|
Breckenridge RJ, Nicholson SH, Nicol AJ, Suckling CJ, Leigh B, Iversen L. Inhibition of [3H]GABA binding to postsynaptic receptors in human cerebellar synaptic membranes by carboxyl and amino derivatives of GABA. J Neurochem 1981; 37:837-44. [PMID: 6275034 DOI: 10.1111/j.1471-4159.1981.tb04469.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Fifty synthetic analogues of GABA were tested for their ability ot interact with GABA receptors, using [3H]GABA binding to human cerebellar membranes as an in vitro model. The most active compounds were found to be aliphatic and heterocyclic aminosulphonic acids. Compounds with highly substituted nitrogen atoms were only weakly active unless a long alkyl chain, which can interact with the postsynaptic membrane, was present. It was concluded that a pyramidal nitrogen atom is favoured fro binding of GABA analogues to human cerebellar membranes.
Collapse
|
15
|
Bowery NG, Doble A, Hill DR, Hudson AL, Shaw JS, Turnbull MJ, Warrington R. Bicuculline-insensitive GABA receptors on peripheral autonomic nerve terminals. Eur J Pharmacol 1981; 71:53-70. [PMID: 6263651 DOI: 10.1016/0014-2999(81)90386-1] [Citation(s) in RCA: 326] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The action of gamma-aminobutyric acid (GABA) and related compounds on rat isolated atria and mouse and guinea pig isolated vas deferens has been studied. GABA depressed the evoked but not basal release of [3H]noradrenaline from atria (IC50 4 micro M) and reduced the twitch responses of the vas deferens (IC50 3 micro M) in a dose-dependent manner. These depressant effects were not prevented by recognized GABA antagonists such as bicuculline and picrotoxin. Numerous GABA analogues, in particular 3-aminopropanesulphonic acid, failed to mimic the action of GABA. However, beta-p-chlorophenyl GABA (baclofen) was stereospecifically active. Other related beta-substituted derivatives were also active but to a lesser degree than GABA. Pretreatment of the vas deferens with the neuronal GABA uptake inhibitors 2,4-diaminobutyric acid or cis-3-aminocyclohexanecarboxylic acid potentiated the action of GABA. These data suggest the presence of a bicuculline-insensitive GABA receptor on autonomic nerve terminals. Preliminary observations indicate a lack of chloride ion dependence in the action of GABA at this site.
Collapse
|
16
|
Allan RD, Evans RH, Johnston GA. gamma-Aminobutyric acid agonists: an in vitro comparison between depression of spinal synaptic activity and depolarization of spinal root fibres in the rat. Br J Pharmacol 1980; 70:609-15. [PMID: 6258682 PMCID: PMC2044373 DOI: 10.1111/j.1476-5381.1980.tb09779.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
1 Relative molar potencies, of a range of gamma-aminobutyrate (GABA)-related agonists, for depolarization of isolated spinal roots have been compared with their potencies for depression of spontaneous synaptic activity, recorded in ventral roots of hemisected spinal cord preparations from 3 to 9-day-old rats. Both effects were sensitive to antagonism by bicuculline. 2 The depolarizing potencies of the series were not parallelled by their depressant potencies. This disparity was shown most strongly by 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP) which was 20 times stronger than GABA in depolarizing root fibres and 20 times stronger than GABA in its depressant action and by (+)-cis-3-aminocyclopentane-carboxylic acid (17 times weaker than GABA on root fibres and 42 times stronger than GABA as a depressant). 3 The effect of uptake on these relative potencies is discussed and it is concluded that fibre depolarization and depression are probably mediated by different types of bicuculline-sensitive receptor. 4 The depolarizing potencies of the agonists showed a strong correlation with previously reported data for displacement of labelled GABA from in vitro rat brain membrane preparations (correlation coefficient 0.90, P less than 0.001). However, the relative depressant potencies showed no such correlation with binding data (correlation coefficient 0.50, P less than 0.05).
Collapse
|
17
|
Curtis DR, Bornstein JC, Lodge D. In vivo analysis of GABA receptors on primary afferent terminations in the cat. Brain Res 1980; 194:255-8. [PMID: 6247036 DOI: 10.1016/0006-8993(80)91339-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
18
|
|
19
|
Meldrum B, Pedley T, Horton R, Anlezark G, Franks A. Epileptogenic and anticonvulsant effects of GABA agonists and GABA uptake inhibitors. Brain Res Bull 1980. [DOI: 10.1016/0361-9230(80)90113-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
20
|
Desarmenien M, Headley P, Santangelo F, Feltz P. The effects of various GABA-mimetics on dorsal root ganglion neurones in vitro: A physiological analysis. Brain Res Bull 1980. [DOI: 10.1016/0361-9230(80)90075-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
21
|
Characterisation of the binding of 3H-isoguvacine, a γ-aminobutyric acid agonist, to brain synaptosomal membranes. Brain Res Bull 1980. [DOI: 10.1016/0361-9230(80)90024-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
22
|
Bowery N, Doble A, Hill D, Hudson A, Shaw J, Turnbull M. β-Chlorophenyl GABA (Baclofen) is a selective ligand for a novel GABA receptor on nerve terminals. Brain Res Bull 1980. [DOI: 10.1016/0361-9230(80)90080-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
23
|
Towart R, Kazda S. The cellular mechanism of action of nimodipine (BAY e 9736), a new calcium antagonist [proceedings]. Br J Pharmacol 1979; 67:409P-410P. [PMID: 497542 PMCID: PMC2044020 DOI: 10.1111/j.1476-5381.1979.tb08695.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
|
24
|
|