Figure 1.

Ghrelin increases [Ca²⁺]_i in SFO neurons. A, B, [Ca²⁺]_i measured in individual SFO neurons by microfluorometry of the Ca²⁺-sensitive dye fura-2 demonstrates that ghrelin treatment causes transient increases in [Ca²⁺]_i that are reversible after removal of ghrelin from the bath solution. The amplitude and duration of responses varied among cells. In some SFO neurons, the effect was repeatable, although of smaller magnitude, thus suggesting that some desensitization may be occurring (B). C, Mean change in [Ca²⁺]_i measured relative to baseline in control cells treated with HBSS (n = 43), neurons responding to 10 nm ghrelin (n = 12; *p < 0.05), cells treated with 10 nm ghrelin in the presence of [d-Lys-3]-GHRP-6 (lined bar; n = 17; p > 0.05), and cells treated with 10 nm ghrelin in the presence of TTX (n = 6; p > 0.05). D, Ethidium bromide-stained agarose gel of the RT-PCR products generated with the GHSR and synaptotagmin-1 (synap-1) primers. Lane 1, DNA marker; lane 2, GHSR1a receptor (261 bp; specifically detects only the active GHSR1a receptor); lane 3, GHSR receptor (321 bp; detects both GHSR1a and GHSR1b receptors); lane 4, synaptotagmin-1 (199 bases); lane 5, negative control.