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Cholera and pertussis toxins reveal multiple regulation of cAMP levels in the rabbit carotid body


, : Cholera and pertussis toxins reveal multiple regulation of cAMP levels in the rabbit carotid body. European Journal Of Neuroscience. 8(11): 2320-2327

It is known that hypoxia (PO2 approximately equal to 66-18 mm Hg), acting via unknown receptors, increases carotid body cAMP levels in Ca(2+)-free solutions, indicating that low PO2 activates adenylate cyclases independently of the action of the released neurotransmitters. The aim of the present work was to investigate the involvement of G proteins in the genesis of the basal level of cAMP and on the increase in cAMP induced by low PO2. In carotid body homogenates, cholera toxin- and pertussis toxin-induced [32P]ADP-ribosylation of two protein bands of approximately equal to 42 and 45 kDa, and approximately equal to 39 and 40 kDa respectively; in both cases, prior incubation of the carotid bodies with the toxins reduced [32P]ADP-ribosylation by > 90%. In intact carotid bodies, cholera toxin treatment increased cAMP levels more in normoxic than in hypoxic organs, indicating that hypoxia releases neurotransmitters acting on receptors negatively coupled to adenylate cyclases. Cholera toxin-treated carotid bodies incubated in Ca(2+)-free solution had identical cAMP levels in normoxia and in hypoxia. In pertussis toxin-treated normoxic carotid bodies the cAMP level was close to control, but in pertussis toxin-treated hypoxic carotid bodies cAMP rose to a level similar to those seen in normoxic cholera toxin-treated organs, indicating that low PO2 releases neurotransmitters acting on receptors positively coupled to adenylate cyclases. Pertussis toxin-treated carotid bodies incubated in Ca(2+)-free solution lost their capacity to increase cAMP in response to hypoxia, indicating that a G protein sensitive to pertussis toxin is needed for this response. This implies that the carotid bodies express a pertussis toxin-sensitive G protein positively coupled to adenylate cyclases, or that a Gs protein requiring the cooperative action of Go/Gi donated beta gamma subunits mediates the increase in cAMP level produced by hypoxia.

US$19.90

PMID: 8950096

DOI: 10.1111/j.1460-9568.1996.tb01195.x


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McGowan, C., 1989: Leptopterygius tenuirostris and other long-snouted ichthyosaurs from the English Lower Lias. One of the commonest ichthyosaurs from the English Lower Lias is the long-snouted species Leptopterygius tenuirostris, known principally from Street, Somerset. Because of the vagaries of preservation there are few complete skeletons, and the probl...

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Popa, M.; Cristea, M.; Dutu, H., 1988: Experimental results concerning the inheritance of response to attack by Fusarium graminearum in maize. A study was made during 1985-86 of response to F. graminearum [Gibberella zeae] under artificial infection in 6 parent lines and 6 hybrids in the F1, F2, BC1 and BC2. The effect of genotype was determined for 3 hybrids in respect of ear infection...

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