Fish, frogs, flies and other fauna in scientific firsts

Austrian scientist Otto Loewi observes parallel activity in two frog hearts suspended in saline, theorizing that a chemical messenger he dubs ‘vagusstoff’ traveled through the solution — the first identified neurotransmitter.

Biologist Seymour Benzer and a colleague demonstrate that mutations in a fruit fly gene dubbed PER disrupt the fly’s circadian rhythm, launching Drosophila melanogaster as a model for the study of how genes control behavior.

Studies show that C. elegans is capable of habituation, a simple form of learning that may be disrupted in autism.

Scientists create one of the first invertebrate models of autism: a strain of C. elegans with a faulty version of the roundworm’s neuroligin gene NLG1.

Researchers report that fruit flies in an enclosure tend to keep a reliable amount of space between them, an observation that can be used to investigate how mutations in autism-linked genes affect social behavior.

Zebrafish larvae lacking the autism-linked gene CNTNAP2 are hyperactive at night, but adding estrogen-like compounds to their tank calms the fish — demonstrating a use for the animals in screening potential autism treatments.

Researchers identify neurons in the forebrain of zebrafish that support their social interactions, suggesting that zebrafish can be used to probe social brain circuitry.

Scientists find that food moves through the gut slowly in zebrafish larvae with SHANK3 mutations, providing a clue to the roots of digestive problems associated with autism.

Like their mouse counterparts, zebrafish lacking the autism-linked gene RELN show little interest in socializing with unfamiliar fish, supporting use of the fish as a model for social difficulties in autism.

Zebrafish larvae lacking FMR1, the gene altered in fragile X syndrome, are hypersensitive to sound, suggesting that zebrafish can be used to study sensory processing differences in autism.