Hydrogen Sulphide Flashcards

1
Q

what is hydrogen sulphide?

A

a messenger molecule that is extremely toxic

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2
Q

describe h2s in a solution?

A

within a solution hydrogen sulphide is ionised

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3
Q

what are the biological sources of h2s?

A

hydrogen sulphide comes from three cysteine enzymes: CSE, CBS, 3-MST

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4
Q

what are two extra biological sources of hydrogen sulphide?

A

intestinal flora

iron-sulphur clusters

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5
Q

what is sulfyhdration?

A

the addition of a sulphur to a cysteine residue to form sulphur rings

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6
Q

what is evidence for the function of H2S in the cardiovascular system?

A

CSE enzyme knockout in mice shows hypertension and impaired vasodilation

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7
Q

what is the functions of H2S in the cardiovascular system?

A

enhances K-atp channels

inhibitis phosphodiesterases

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8
Q

what is dysregulated H2S biosynthesis?

A

it occurs during pregnancy in maternal hypertension and preeclampsia

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9
Q

describe H2S in the gut…

A

in the gut, hydrogen sulphide is produced by resident microbes and is involved in smooth muscle relaxation, protecting against inflammation, ischemic damage protection, and protecting from alcohol-induced gastritis

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10
Q

describe the distribution of H2S synthesis enzymes in the nervous system

A

in the nervous system, CBS enzymes are found in glia and astrocytes, and CSE and 3-MST enzymes are found in neurons - the multiple sources for hydrogen sulphide indicate its importance within the nervous system

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11
Q

describe the different roles hydrogen sulphide plays in the central nervous system…

A

involved in long term potentiation (as this process most likely occurs by sulfhydration)
dysregulation of the hydrogen sulphide metabolism is also present in ASD and PD

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12
Q

what is synergy?

A

the interaction or cooperation of two or more substances to produce an outcome which is greater than the sum of their individual effects.

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13
Q

what synergetic relationships exist between hydrogen sulphide and nitric oxide?

A

in the aorta, low concentrations of hydrogen sulphide increase nitric oxide induced smooth muscle relaxation

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14
Q

describe the synergy between hydrogen sulphide and nitric oxide…

A

the enzymes which produce H2S and NO are co-located. HSH could react with nitrite to produce HSNO

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15
Q

what is thionitrous acid?

A

HSNO, produced by co-localised reaction of HSH with nitrite

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