Electrophysiological characterization of male goldfish (Carassius auratus) ventral preoptic area neurons receiving olfactory inputs

Abstract

Chemical communication via sex pheromones is critical for successful reproduction but the underlying neural mechanisms are not well-understood. The goldfish is a tractable model because sex pheromones have been well-characterized in this species. We used male goldfish forebrain explants in vitro and performed whole-cell current clamp recordings from single neurons in the ventral preoptic area (vPOA) to characterize their membrane properties and synaptic inputs from the olfactory bulbs (OB). Principle component and cluster analyses based on intrinsic membrane properties of vPOA neurons (N = 107) revealed five (I–V) distinct cell groups. These cells displayed differences in their input resistance (Rinput: I < II < IV < III = V), time constant (TC: I = II < IV < III = V), and threshold current (Ithreshold: I > II = IV > III = V). Evidence from electrical stimulation of the OB and application of receptor antagonists suggests that vPOA neurons receive monosynaptic glutamatergic inputs via the medial olfactory tract, with connectivity varying among neuronal groups [I (24%), II (40%), III (0%), IV (34%), and V (2%)].

GPER/GPR30, a membrane estrogen receptor, is expressed in the brain and retina of a social fish (Carassius auratus) and colocalizes with isotocin

“…Both the Vs and the POA are areas that express aromatase in goldfish (Gelinas and Callard, ; Gelinas and Callard, ) and are involved in the regulation of courtship behavior (Kyle and Peter, ). The preoptic area receives direct retinal projections (Springer and Gaffney, ), as well as olfactory input (Levine and Dethier, ; Lado et al, ), so it could play a critical role in integrating sexual stimuli processed in multiple sensory modalities into behavioral output. Interestingly, isotocin produced in the preoptic area can, like E 2 , stimulate approach responses to the visual stimuli of conspecifics within 5–20 minutes in goldfish males (Thompson and Walton, ), raising the possibility that estrogenic effects on these peptidergic neurons, perhaps through GPR30 signaling mechanisms, could also play some role in E 2 's behavioral effects.…”

“…Both the Vs and the POA are areas that express aromatase in goldfish (Gelinas and Callard, 1993; and are involved in the regulation of courtship behavior (Kyle and Peter, 1982). The preoptic area receives direct retinal projections (Springer and Gaffney, 1981), as well as olfactory input (Levine and Dethier, 1985;Lado et al, 2014), so it could play a critical role in integrating sexual stimuli processed in multiple sensory modalities into behavioral output. Interestingly, isotocin produced in the preoptic area can, like E 2 , stimulate approach responses to the visual stimuli of conspecifics within 5-20 minutes in goldfish males , raising the possibility that estrogenic effects on these Alternatively, or in addition, rapid estrogenic effects on male goldfish social approach behavior could be mediated through actions in visual processing areas, including the retina, where increased visual sensitivity could help males detect potential mates, and/or its primary target, the optic tectum (OT), which plays a critical role in visual orienting (Springer et al, 1977).…”

The Effect of Laserpuncture on Accelerate Gonadal Maturity of Female Striped Catfish (Pangasianodon hypophthalmus)

“…An increase in formation of protein kinase C (PKC). resulting in the release of neurotransmitters through exocytosis into the gaps in the synapses and continued to the brain thereby stimulating GABAergic neurons to synthesize Gama Amino Butyrad Acid (GABA) which will stimulate the release of gonadotropin hormones (GtH-I and GtH-II) (Mueller et al, 2008;Lado et al, 2014;Watanabe et al, 2014).The increase in the hormone GtH-I stimulates theca cells to produce the hormone 17β-estradiol which stimulates the synthesis of vitellogenin in the liver [10].and GtH-II will stimulate granulosa cells. which plays a role in the final oocyte maturation and stimulates ovulation and spawning [1].…”