Single-cell analysis of peptide expression and electrophysiology of right parietal neurons involved in male copulation behavior of a simultaneous hermaphrodite

Abstract

Male copulation is a complex behavior that requires coordinated communication between the nervous system and the peripheral reproductive organs involved in mating. In hermaphroditic animals, such as the freshwater snail Lymnaea stagnalis, this complexity increases since the animal can behave both as male and female. The performance of the sexual role as a male is coordinated via a neuronal communication regulated by many peptidergic neurons, clustered in the cerebral and pedal ganglia and dispersed in the pleural and parietal ganglia. By combining single-cell matrix-assisted laser mass spectrometry with retrograde staining and electrophysiology, we analyzed neuropeptide expression of single neurons of the right parietal ganglion and their axonal projections into the penial nerve. Based on the neuropeptide profile of these neurons, we were able to reconstruct a chemical map of the right parietal ganglion revealing a striking correlation with the earlier electrophysiological and neuroanatomical studies. Neurons can be divided into two main groups: (i) neurons that express heptapeptides and (ii) neurons that do not. The neuronal projection of the different neurons into the penial nerve reveals a pattern where (spontaneous) activity is related to branching pattern. This heterogeneity in both neurochemical anatomy and branching pattern of the parietal neurons reflects the complexity of the peptidergic neurotransmission involved in the regulation of male mating behavior in this simultaneous hermaphrodite.

FMRF‐NH2‐related neuropeptides in Biomphalaria spp., intermediate hosts for schistosomiasis: Precursor organization and immunohistochemical localization

“…Projections to the penial nerve from the left pleural and parietal ganglia were also examined, as the innervation of male reproductive structures by FaRP heptapeptides originates from pleural and parietal neurons in L . stagnalis (El Filali et al, 2015; van Golen et al, 1995). Backfills of the penis nerve labeled approximately 20 cells dispersed throughout the left pleural ganglion (Figure 6(a,d)).…”

“…In L . stagnalis , innervation of the male reproductive system by the FaRP heptapeptides originates from neurons in the pleural ganglia and the B group of the parietal ganglia (de Lange, Joosse, & van Minnen, 1998; El Filali et al, 2015; van Golen et al, 1995). Whether the male mating system of Biomphalaria is innervated by central neurons that express the Bgl‐FaRP2/3 heptapeptides remains uncertain, as FMRF‐NH 2 ‐li projections to the penial nerve from the pleural or parietal ganglia were not observed (Figure 6).…”

The genome of the simultaneously hermaphroditic snail Lymnaea stagnalis reveals an evolutionary expansion of FMRFamide-like receptors

“…It is worth illustrating this with the multitude of roles that FMRFamide and its co-expressed peptides ful l [102][103][104][105] next to being cardio-excitatory 106 . These tetra-and heptapeptides have been shown to be important for the ne coordination of the execution of male mating behaviour and insemination 105,107 .…”

Neuropeptide Localization in Lymnaea stagnalis: From the Central Nervous System to Subcellular Compartments

“…By combining retrograde filling and MALDI-MS analysis, multiple connected neurons from the RPaG were analyzed for their neuropeptide components. It was determined that neurons connected to the male copulation circuit in the RPaG can be divided into two groups: neurons that express FMRF heptapeptides and neurons that do not ( El Filali et al, 2015 ). The combination of retrograde filling with MS technologies is becoming a powerful tool in exploring chemical communication within neuronal circuits.…”