Distribution of GABA‐like immunoreactivity in the brain of the honeybee

Abstract

The distribution of GABA-like immunoreactivity in the brain of the honeybee was investigated with antisera generated against GABA protein conjugates. The binding of the antisera in paraffin serial sections was studied with the peroxidase-antiperoxidase method. GABA-like immunoreactive fibers appeared in all main neuropile areas. The staining of the optic lobes showed pronounced stratification. The receptor cells of compound eyes, ocelli, and antennae were not labelled. Several prominent fiber tracts showed GABA-like immunoreactivity, whereas other tracts were devoid of staining. There are no major immunoreactive commissures linking the two brain hemispheres with the exception of small commissures that bridge short distances between the beta-lobes and the antennal lobes. Several fibers in the cervical connective were also labelled; some of those may descend from the suboesophageal ganglion to the thoracic ganglia. The dense reactivity seen in the optic and antennal neuropiles implies that GABA is more important in mediating local rather than more distant neural interactions.

The Processing of Color, Motion, and Stimulus Timing Are Anatomically Segregated in the Bumblebee Brain

“…As observed in the honeybee (Schäfer and Bicker, 1986), GABA was distributed differently among the lobula layers in bumblebees in a large number of neurites (Fig. 3C,D).…”

“…3). In past studies, researchers found that lobula layers are evident in honeybee brain tissue immunolabeled for serotonin, octopamine, GABA, and acetylcholinesterase (Schäfer and Bicker, 1986; Kre- D) view, the different layout of GABA (white bands) are combined with the layout of the wide-field layer 1-4 (red), layer 5-6 neurons (blue), and columnar layer 1-6 neurons (green). These neurons predominantly exit the lobula via different tracts, which include the aott, psot, piot, and lot.…”

Calcium Current Diversity in Physiologically Different Local Interneuron Types of the Antennal Lobe

“…In subsequent studies, GABAergic LNs have been reported in various insect species (Schäfer and Bicker, 1986;Leitch and Laurent, 1996;Iwano and Kanzaki, 2005;Wilson and Laurent, 2005) and the importance of GABAergic, inhibitory LNs for odor information processing was clearly shown (Stopfer et al, 1997;Sachse and Galizia, 2002;Wilson and Laurent, 2005). In parallel, however, it became increasingly clear that the LNs are a more heterogeneous population of neurons than previously thought.…”

“…Historically, LNs have been regarded mostly as GABAergic, inhibitory neurons, and GABAergic LNs have been reported in the AL of various insect species including A. mellifera (Schäfer and Bicker, 1986), Bombyx mori (Iwano and Kanzaki, 2005;Seki and Kanzaki, 2008), D. melanogaster (Wilson and Laurent, 2005), M. sexta (Hoskins et al, 1986), P. americana (Distler, 1989), and S. americana (Leitch and Laurent, 1996). Immunohistochemical, mass-spectrometric and physiological studies, however, showed that the LNs are biochemically a more heterogeneous population of neurons than previously thought.…”

Is GABA present in the nervous system of acoel plathelminthes? An electron immunocytochemical study

“…Among the invertebrates, the GABA neurotransmitter has so far been revealed and localized only in insects, molluscs, and nematodes (Bicker et al, 1985;Datum et al, 1986;Hoskins et al, 1986;Meyer et al, 1986;Schafer & Bicker, 1986;Vitellaro et al, 1988;Distler, 1990;Malum, 1991;Richmond et al, 1991;Guastella & Stretton, 1991;Watson & England, 199D. In insects, GA-BA-ir neurone profiles and synapses contain small immunolabelled clear vesicles (25 nm long), while in molluscs the GABA immunoreactivity seems to be present on vesicles of the same size, but of a pleiomorphic shape, such as those with an electron-dense core present in mammalian nervous tissue (Van den Pol, 1986;De Biasi et al, 1986;Vitellaro et al, 1988).…”