Oxytocin‐like receptor expression in evolutionarily conserved nodes of a vocal network associated with male courtship in a teleost fish. Issue 6 (3rd November 2021)

• Record Type: Journal Article
• Authors: Schuppe, Eric R.; Zhang, Melissa D.; Perelmuter, Jonathan T.; Marchaterre, Margaret A.; Bass, Andrew H.
• Is Part Of: Journal of comparative neurology. Volume 530:Issue 6(2022)
• Page Start: 903
• Page End: 922
• Publication Date: 2021-11-03
• Subjects: isotocin receptor -- oxytocin -- teleost fish -- vocal communication -- vocal motor network; Comparative neurobiology -- Periodicals; Neurology -- Periodicals; 616
• DOI: 10.1002/cne.25257
• Languages: English
• ISSNs: 0021-9967

Abstract

Abstract: Neuropeptides, including oxytocin‐like peptides, are a conserved group of hormones that regulate a wide range of social behaviors, including vocal communication. In the current study, we evaluate whether putative brain sites for the actions of isotocin (IT), the oxytocin (OT) homolog of teleost fishes are associated with vocal courtship and circuitry in the plainfin midshipman fish ( Porichthys notatus ). During the breeding season, nesting males produce advertisement calls known as "hums" to acoustically court females at night and attract them to nests. We first identify IT receptor (ITR) mRNA in evolutionarily conserved regions of the forebrain preoptic area (POA), anterior hypothalamus (AH), and midbrain periaqueductal gray (PAG), and in two topographically separate populations within the hindbrain vocal pattern generator– duration‐coding vocal prepacemaker (VPP) and amplitude‐coding vocal motor nuclei (VMN) that also innervate vocal muscles. We also verify that ITR expression overlaps known distribution sites of OT‐like immunoreactive fibers. Next, using phosphorylated ribosomal subunit 6 (pS6) as a marker for activated neurons, we demonstrate that ITR‐containing neurons in the anterior parvocellular POA, AH, PAG, VPP, and VMN are activated in humming males. Posterior parvocellular and magno/gigantocellular divisions of the POA remain constitutively active in nonhumming males that are also in a reproductive state. Together with prior studies of midshipman fish and other vertebrates, our findings suggest that IT‐signaling influences male courtship behavior, in part, by acting on brain regions that broadly influence behavioral state (POA) as well as the initiation (POA and PAG) and temporal structure (VPP and VMN) of advertisement hums. Abstract : We examined sites of isotocin (IT) action throughout an evolutionarily conserved vocal motor network that is shared by nearly all vocal vertebrates. Using the highly vocal plainfin midshipman ( Porichthys notatus ) fish, we find that IT receptor (R) mRNA and IT‐like fibers are widespread throughout the vocal motor network. Next, using a neural activity marker, we show that ITR dense nuclei within forebrain and midbrain nodes are differentially activated during vocal courtship. Midshipman photo credit: Margaret Marchaterre