Drug-Induced Localized Sweating in Neonates

Abstract

The effect of cholinesterase inhibition on sweat glands of neonates was explored through the local action of intradermally administered neostigmine. All 15 full-size neonates reacted to concentrations of 10 to 10 while only four of 17 low-birth-weight infants were responsive. This differential responsiveness is highly significant (P = 0.01). Differences are even greater when related to gestational age. In addition, subthreshold combinations of neostigmine and acetylcholine were given to three premature and four mature infants in order to potentiate pharmacologic stimuli. None of the premature infants responded to doses as high as paired half-maximal concentrations of each drug, while all mature infants showed sweating. Potentiation could not be shown even in mature neonates with pilocarpine and acetylcholine. This study shows that sweat glands are responsive to endogenous acetylcholine in mature neonates but not in those born prematurely.In recently reported studies the functional development of sweat glands of newborn infants has been explored by the method of in¬ tradermal pharmacologie stimula¬ tion, a method frequently used in adults.1 :' In tests performed with epinephrine and acetylcholine, the responsiveness of the glands to both drugs was found to be remarkably high in full-size neonates but sig¬ nificantly lacking in infants of low birth weight. Glandular reactivity appears to be a function of gesta¬ tional age. Similar tests with nico¬ tine5 showed that the highest concen¬ tration required for eliciting axon reflex sweating in mature neonates failed to be effective in prematurely born infants. Foster et ale deter¬ mined sweating responses to an in¬ tradermal standard dose of ace¬ tylcholine by measuring total evap¬ orative loss from the test areas.They found high glandular respon¬ siveness in mature neonates and lack of reactivity in prematurely born in¬ fants.In the present study we made use of the cholinesterase-inhibiting ac¬ tion of neostigmine to observe the effect of enhanced accumulation of endogenous acetylcholine on the sweat glands of mature and imma¬ ture neonates. Also included are ob¬ servations on the comparative reac¬ tivity of sweat glands to exogenous and endogenous acetylcholine and their potentiating effect when used in combination. Subjects and MethodsStimulation tests were performed on healthy neonates born at Metropolitan Hospital. Excluded were babies with ill¬ ness as well as those in critical condition due to extreme immaturity. Written, in¬ formed, parental consent was obtained in each instance. The selected subjects were tested at ages ranging from the first to the eighth day of life, but not earlier than 14 hours after birth. No repeat tests of the same infant at various ages are in¬ cluded in this report. Full-size and lowbirth-weight neonates are represented in approximately equal proportions; their gestational ages range from 27 to 41 com¬ pleted weeks. Gestational age was calcu¬ lated as weeks completed from the onset of the last normal menstrual period to the birth of th...