Neural substrate and allatostatin-like innervation of the gut of Locusta migratoria

The neural and peptidergic control of gut contraction in Locusta migratoria: the effect of an FGLa/AST

“…During periods of water and food deprivation, FGLa/ASTs may be released into the haemolymph to modulate local midgut contraction, thus decreasing metabolic activity and increasing the time the food bolus remains in this region, allowing increased time for chemical digestion and the absorption of nutrients. This is in line with the suggestion that these peptides function as neurotransmitters/neuromodulators at the locust gut, based on the presence of networks of FGLa/AST-like immunoreactive processes and varicosities on the surface of the foregut, midgut and hindgut (Robertson and Lange, 2010). In addition, FGLa/AST-like peptides have been detected in the haemolymph and are released from the cockroach midgut into the haemolymph during feeding, acting as endocrine hormones (Woodhead et al, 1993;Yu et al, 1995).…”

“…The Journal of Experimental Biology 215 (19) cell bodies within the eighth abdominal ganglion (Robertson and Lange, 2010). These cells may release FGLa/AST-like peptides locally as neurotransmitters or neuromodulators onto the gut tissue or into the haemolymph to act as neurohormones.…”

“…The frontal ganglion is involved in the control of movements of the anterior foregut or pharynx, and is the major source of innervations to the dilator muscles (Albrecht, 1953;Zilberstein and Ayali, 2002;Bräunig, 2008). Nerves arising from the paired ventricular (ingluvial) ganglia located bilaterally on the foregut directly supply the innervation to the posterior foregut, while the eleventh sternal nerve of the eighth abdominal ganglion innervates the hindgut (Robertson and Lange, 2010;Donini et al, 2002). The midgut receives innervation from both the STNS and the CNS, which results in an extensive nerve plexus over the entire midgut (Robertson and Lange, 2010;Donini et al, 2002;Albrecht, 1953).…”

“…The detection of several myoactive peptides within cell bodies of the STNS and CNS, and especially within the innervation to each of the gut regions suggests that peptides are involved in the neuromodulation of feeding and digestion, or in the control of gut motility (see Gäde et al, 1997;Robertson and Lange, 2010;Wei et al, 2000). For example, proctolin-like immunoreactivity is associated with cell bodies of the ganglia of the STNS and CNS, as well as within the nerves that innervate the gut (Clark et al, 2006a).…”

“…For example, proctolin-like immunoreactivity is associated with cell bodies of the ganglia of the STNS and CNS, as well as within the nerves that innervate the gut (Clark et al, 2006a). The allatostatin (AST) family referred to as FGLa/ASTs (previously known as A-type or cockroach type ASTs ending in the amino acid sequence FGLamide) (see Coast and Schooley, 2011) are pleiotropic, and based on their distribution in the locust CNS and STNS and innervation to the gut it has been suggested that FGLa/ASTs also regulate digestive functions (Robertson and Lange, 2010).…”