Neuronal substrate of electrically induced grooming in the PVH of the rat: involvement of oxytocinergic systems?

Electrical stimulation of the paraventricular (PVH) and adjacent hypothalamic area evokes self-grooming behaviour. Current intensity thresholds for grooming can be obtained depending on the exact localization of the electrode site. Sites localized at greater distance of the center of the grooming area evoke grooming at greater latencies and higher current intensity, or no grooming at all. Results are compared with injections of neuroactive substances into the PVH from previous studies, which showed a similar site specificity for grooming. We found similarity in the distribution of electrode sites in the paraventricular and anterior hypothalamic areas at which grooming is induced, and hypothalamic immunoreactive oxytocinergic neurons and fibres. In addition, we reported earlier that oxytocin infusions into the PVH in resting animals induce grooming, in contrast to other grooming-related peptides, such as alpha-melanocyte-stimulating hormone. We hypothesize that electrical stimulation may induce grooming by activation of oxytocinergic systems originating from the PVH.