Prolactin‐releasing peptide affects gastric motor function in rat by modulating synaptic transmission in the dorsal vagal complex

• DOI: 10.1113/jphysiol.2004.072736
• Publication Date: 2004-10-15T00:14:23Z
• Authors: Gintautas Grabauskas; Shi‐Yi Zhou; Sudipto Das; Yuanxu Lu; Chung Owyang; Hylan C. Moises
• Keywords: Dorsal motor nucleus; Area postrema; Solitary tract; Solitary nucleus

Prolactin‐releasing peptide (PrRP) is a recently discovered neuropeptide implicated in the central control of feeding behaviour and autonomic homeostasis. PrRP‐containing neurones PrRP receptor mRNA are found abundance caudal portion nucleus tractus solitarius (NTS), an area which together with dorsal motor vagus (DMV) comprises integrated structure, vagal complex (DVC) that processes visceral afferent signals from provides parasympathetic innervation to gastrointestinal tract. In this study, microinjection experiments were conducted vivo combination whole‐cell recording rat medullary slices test hypothesis plays role gastric function, acting within DVC modulate activity preganglionic supply stomach. Microinjection (0.2 pmol (20 nl) −1 ) into DMV at level postrema (+0.2 +0.6 mm calamus scriptorius, CS) markedly stimulated contractions increased intragastric pressure (IGP). Conversely, administration sites obex (0.0 –0.3 decreased IGP reduced phasic contractions. These effects occurred without change mean arterial abolished by ipsilateral vagotomy , indicating mediation via vagal‐dependent mechanism(s). The pattern responses evoked mimicked produced l ‐glutamate same sites, both following local NMDA non‐NMDA‐type glutamate antagonists. On other hand, medial or comissural solitary tract (mNTS comNTS, respectively) resulted less robust changes smaller percentage animals, accompanied marked alterations pressure. Superfusion brain (100–300 n m small depolarization spontaneous firing 10 30 retrogradely labelled gastric‐projecting neurones. excitatory blocked TTX (2 μ specific antagonists, they interactions presynaptic site. Congruent this, amplitude postsynaptic currents (EPSCs, 154 ± 33%, 12 25 neurones) electrical stimulation mNTS comNTS. addition, paired‐pulse ratio EPSCs two identical stimuli delivered 100 ms apart (from 0.95 0.08 0.71 0.11, P < 0.05 ), whereas it did not affect inward exogenous application slice. frequency, but action potential‐independent miniature was also PrRP, suggesting least part receptors on nerve terminals enhance glutamatergic transmission. recordings obtained separate group slices, we observe any direct discharge excitability either comNTS ( = 31) . data indicate may act regulate function modulating efficacy conventional synaptic inputs NTS onto