Interspecificity of lipid-regulating factors from insect corpus cardiacum

1972 ◽  
Vol 50 (1) ◽  
pp. 63-65 ◽  
Author(s):  
R. G. H. Downer

Aqueous extracts of corpus cardiacum from Periplaneta americana L. elicit the characteristic locust response of hyperlipemia when injected into adult male Locusta migratoria migratoides R. and F. Conversely, gland extracts of L. m. migratoides cause the typical cockroach response of hypolipemia when injected into adult male P. americana.It is proposed that similar factors are present in both species with specificity being determined at the site of action.

1977 ◽  
Vol 71 (1) ◽  
pp. 49-66
Author(s):  
LOIS E. TUCKER

Changes in live weight and in the water, Na+ and K+ content of the tissues and faeces have been examined in adult male Periplaneta americana in various states of hydration. During dehydration the haemolymph volume decreases markedly, but the Na+ and K+ concentrations rise only slightly. Less than 25% of the Na+ removed from the haemolymph during dehydration was found to be excreted, but the K+ excreted during dehydration was in excess of that removed from the haemolymph alone. It seems likely that the major tissue for regulating the haemolymph Na+ during dehydration and rehydration is the fat body, in which dehydration causes an increase, and rehydration a decrease, in the Na:K ratio. The Na+ and K+ content of the fat body was found to be variable in both hydrated and dehydrated animals and absolute changes in the ion content of the tissue could not be estimated because of unknown changes in the amount of food reserves and excretory products.


1972 ◽  
Vol 57 (3) ◽  
pp. 755-763
Author(s):  
E. A. BERNAYS ◽  
R. F. CHAPMAN

1. The electrical resistance across the tips of the maxillary palps is not affected by stimulation of the palps, but increases to the normal level found after feeding as a result of distension of the foregut with agar or injection of corpus cardiacum homogenates into the haemolymph. 2. No increase in resistance occurs if the posterior pharyngeal nerves or the frontal connectives are cut. 3. It is inferred that distension of the foregut stimulates stretch receptors which, acting via the posterior pharyngeal nerves, the frontal connectives and the brain, cause the release of hormone from the storage lobes of the corpora cardiaca. This hormone acts on the terminal sensilla of the palps, causing them to close and so increasing the resistance across the palps. 4. Release of the diuretic hormone is controlled via the same pathway.


1962 ◽  
Vol 39 (3) ◽  
pp. 319-324
Author(s):  
K. G. DAVEY

1. Addition of a homogenate of corpora cardiaca to the fluid bathing an isolated hind gut of Periplaneta produces an increase in tonus, amplitude, frequency and co-ordination of contractions. 2. The corpus cardiacum acts by stimulating cells in the upper colon to release an indolalkylamine. 3. This amine acts on the mucles through a peripheral nervous system which can function in isolation from the central nervous system.


1990 ◽  
Vol 269 (2) ◽  
pp. 309-313 ◽  
Author(s):  
G Gäde ◽  
H Wilps ◽  
R Kellner

A hypertrehalosaemic neuropeptide from the corpora cardiaca of the blowfly Phormia terraenovae has been isolated by reversed-phase h.p.l.c., and its primary structure was determined by pulsed-liquid phase sequencing employing Edman chemistry after enzymically deblocking the N-terminal pyroglutamate residue. The C-terminus was also blocked, as indicated by the lack of digestion when the peptide was incubated with carboxypeptidase A. The octapeptide has the sequence pGlu-Leu-Thr-Phe-Ser-Pro-Asp-Trp-NH2 and is clearly defined as a novel member of the RPCH/AKH (red-pigment-concentrating hormone/adipokinetic hormone) family of peptides. It is the first charged member of this family to be found. The synthetic peptide causes an increase in the haemolymph carbohydrate concentration in a dose-dependent fashion in blowflies and therefore is named ‘Phormia terraenovae hypertrehalosaemic hormone’ (Pht-HrTH). In addition, receptors in the fat-body of the American cockroach (Periplaneta americana) recognize the peptide, resulting in carbohydrate elevation in the blood. However, fat-body receptors of the migratory locust (Locusta migratoria) do not recognize this charged molecule, and thus no lipid mobilization is observed in this species.


1984 ◽  
Vol 62 (1) ◽  
pp. 19-22 ◽  
Author(s):  
B. A. Bailey ◽  
R. J. Martin ◽  
R. G. H. Downer

Haemolymph octopamine levels of adult male cockroaches (Periplaneta americana) were monitored using high performance liquid chromatography with electrochemical detection. The octopamine concentration of haemolymph increases rapidly in response to experimental handling and the commencement of flight, with 77 and 123% elevations, respectively, observed within 1 min of initiating these activities. Resting levels are rapidly restored when flight ceases. The results support the suggestion that octopamine mediates a generalized sympathetic-like response to excitation.


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