Phase Transitions and Heterogeneity in Lipid Bilayers

Pagano, R. E.; Cherry, Richard J.; Chapman, D.

doi:10.1126/science.181.4099.557

Cited by 58 publications

(35 citation statements)

References 7 publications

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“…It is well known that the properties of allosteric enzymes can be influenced by compounds unrelated to the specific substrate, and allosteric adrenoceptors could appropriately be influenced by the 'modulator' substance that has been reported to alter the balance of a-and fl-adrenoceptor components of responses of skeletal muscle blood vessels of dogs (Szentivanyi, Kunos & Juhasz-Nagy, 1970) and by thyroid hormone (Kunos, Vermes-Kunos & Nickerson, 1974). The physical state of membrane lipids is also temperature dependent (Pagano, Cherry & Chapman, 1973), and such a change within the critical temperature range could either alter directly the interaction of POB with the receptors or trigger an alteration of membrane receptor protein.…”

Section: Effects Of Phentolamine On Block By and Binding Of [3h]pobmentioning

confidence: 99%

Temperature‐induced interconversion of alpha‐and beta‐adrenoceptors in the frog heart.

Kunos¹,

Nickerson²

1976

The Journal of Physiology

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SUMMARY1. The effect of ambient temperature on the properties of adrenoceptors mediating inotropic responses was assessed in isolated frog hearts on the basis of the effects and tissue uptake of ox-and fl-adrenoceptor antagonists.2. At temperatures of 230 C and above inotropic responses to adrenaline were antagonized by propranolol (0-4-4.0 uM), but were unaffected by phentolamine (26.5 AM) and were potentiated by phenoxybenzamine (POB) (0.7-29.5 AM). Below 170 C the activity of propranolol was reduced at least tenfold, and the a-adrenoceptor antagonists inhibited responses to both adrenaline and isoprenaline, but not those to CaC12.3. The responses of hearts exposed to POB at 140 C and then tested, after thorough washing, at both 14 and 240 C were similarly inhibited at both temperatures, i.e. the usual fl-adrenoceptor response did not appear at the higher temperature. Conversely, exposure to POB at 240 C produced only potentiation at both test temperatures.4

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Section: Effects Of Phentolamine On Block By and Binding Of [3h]pobmentioning

confidence: 99%

Temperature‐induced interconversion of alpha‐and beta‐adrenoceptors in the frog heart.

Kunos¹,

Nickerson²

1976

The Journal of Physiology

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“…In artificial membranes these changes have generally been described as phase transitions, implying that an entire membrane changes from fluid (liquid-crystal) to solid (gel phase) over a narrow temperature range. However, phase changes especially in membranes of mixed lipid species have been discussed in terms of phase separations, rather than as phase transitions (2,3). It has been suggested that several transition temperatures can be defined in mixed lipid membranes, in which classes of lipid molecules coaggregate and solidify when a membrane is cooled, leaving other lipids, with lower melting temperatures still fluid.…”

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Lateral Phase Separation of Lipids in Plasma Membranes: Effect of Temperature on the Mobility of Membrane Antigens

Petit

Edidin

1974

Science

103

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Cooling populations of newly formed mouse human heterokaryons has effects on the intermixing of mouse and human surface antigens which indicate the occurrence of phase separations in membrane lipids. Antigen mixing, previously shown to be due to diffusion in the plane of the membrane, is retarded when cells are cooled from 37 degrees to 21 degrees C, but is then speeded by further cooling to 15 degrees C. This result is in accord with observations on phase separations of lipids in artificial and bacterial membranes.

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“…Membranes were formed from a 1,2-distearoyl-glycero-3-phosphocholine/decane solution. There is also a paper, based on optical reflectivity measurements on membranes from monostearoylglycerol in n-hexadecane, which demonstrated an ;70% increase in membrane thickness when the system was cooled below the tc of 55°C (8).…”

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confidence: 99%

Lipid phase transition in planar bilayer membrane and its effect on carrier- and pore-mediated ion transport.

Boheim¹,

Hanke²,

Eibl³

1980

Proc. Natl. Acad. Sci. U.S.A.

127

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Using mixed-chain lipids, we have recorded cooling and heating curves of planar bilayer membranes while they passed the lipid phase transition range. With unmodified planar bilayers, spontaneous current fluctuations are observed near the lipid phase transition temperature (tc t 290C). This effect coincides with the expected and measured decrease in membrane capacitance. Carrier (valinomycin)-modified planar bilayers exhibit near tc an abrupt change from a high-conducting state above tc to the state ofbare membrane conductance below tc. In contrast to this behavior, planar bilayers modified by pore-forming antibiotics (gramicidin A, alamethicin) do not show any peculiar effect at tc. However, at 22-230C a pronounced maximum in pore-induced conductance is seen. Whereas the gramicidin A pore abruptly stops stepwise fluctuations below 16'C, with alamethicin a few long-lasting pore and pore state fluctuations persist down to 10'C. It is suggested that the carrier may freeze out into the membrane/water interface. The effects observed with pore-forming substances, on the other hand, are interpreted in terms of lateral phase separation into pure lipid and lipid/antibiotic domains. Phase changes are well-known phenomena in artificial lipid/ water systems (1) and biological systems (2). These phase transitions, which may play a role in triggering biological processes (3), can be induced by temperature changes or by interaction of ions with charged membrane lipids (4, 5). A great number of publications report on phase transition phenomena in pure and protein-loaded vesicles and liposomes. Due to the instability of planar bilayer membranes in the solid state, there are so far only two reports on electrochemical measurements in the freezing and melting range of planar lipid bilayer membranes. Experiments carried out on membranes from a 1:1 (wt/wt) mixture of dipalmitoylglycerol and distearoylglycerol in n-decane led to the interpretation that ion carriers became frozen and thus immobile within the membrane phase (6). On the other hand, the ionic conductance induced by the pore-former gramicidin was found to remain unchanged at the transition temperature tc of 41'C. Recently, ion-conducting channels were reported to appear in unmodified planar bilayer membranes at the phase tr of 59°C (7). Membranes were formed from a 1,2-distearoyl-glycero-3-phosphocholine/decane solution. There is also a paper, based on optical reflectivity measurements on membranes from monostearoylglycerol in n-hexadecane, which demonstrated an ;70% increase in membrane thickness when the system was cooled below the tc of 55°C (8).Using saturated mixed-chain lipids with a tc of ;290C, we succeeded in forming virtually solvent-free planar bilayer membranes below and above tc. In this paper we report our investigations on pure and ionophore-modified planar bilayers of this type in the 10-40°C temperature range.

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Phase Transitions and Heterogeneity in Lipid Bilayers

Cited by 58 publications

References 7 publications

Temperature‐induced interconversion of alpha‐and beta‐adrenoceptors in the frog heart.

Temperature‐induced interconversion of alpha‐and beta‐adrenoceptors in the frog heart.

Lateral Phase Separation of Lipids in Plasma Membranes: Effect of Temperature on the Mobility of Membrane Antigens

Lipid phase transition in planar bilayer membrane and its effect on carrier- and pore-mediated ion transport.

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