| Abstract: | In adult male rats, a pretreatment regimen of serial injections of dexamethasone (1 mg/kg), morphine (20 mg/kg) and pentobarbital (40 mg/kg) was evaluated for use in conjunction with studies on the effects of hypothalamic electrical stimulation on prolactin secretion. Serum prolactin levels were measured before and 15 min after electrical and sham stimulation of the hypothalamic arcuate nucleus in rats subjected to either the pharmacological regimen or to pentobarbital anesthesia alone. Pentobarbital alone caused a transient rise in serum prolactin levels, which obscured any effect of electrical or sham stimulation; this interference was not overcome by the addition of dexamethasone and morphine treatment. Thus, the result indicate that the acute stimulatory affect of pentobarbital anesthesia on prolactin release may interfere with further manipulation of prolactin-controlling mechanisms, by either pharmacological or surgical means. Furthermore, the dexamethasone-morphine-pentobarbital pretreated rat does not provide an adequate preparation for studing the effects of electrical stimulation on prolactin secretion. |
